rails-html-sanitizer

Summary

There is a possible cross-site scripting vulnerability in rails-html-sanitizer when the sanitizer is configured to allow an SVG reference element such as <use>. See related GHSA-9wjq-cp2p-hrgf in Loofah, whose SVG local-reference logic rails-html-sanitizer mirrors.

• Versions affected: >= 1.0.3, < 1.7.1
• Not affected: < 1.0.3
• Fixed versions: 1.7.1

Impact

Rails::HTML::PermitScrubber restricts SVG reference elements in the SVG_ALLOW_LOCAL_HREF collection to local, same-document references, but that restriction covered only the xlink:href attribute. Browsers also accept a plain href attribute per the SVG 2 spec, and it was not restricted, so those elements could reference arbitrary external documents. SVG <use> can load and render external SVG content by reference, and if the referenced document is same-origin and contains scripts, it could execute in the context of the sanitized document. <feImage> can load external images, which can be used for tracking.

Applications are impacted only when the allowed tags are overridden to include one of these SVG reference elements, for example <use> or <feImage>. The default allowed tags do not include these SVG elements, so applications using the default configuration are not affected.

Workarounds

Remove the SVG reference elements (such as use and feImage) from the overridden allowed tags. Applications using the default allowed tags are not affected.

References

• GHSA-9wjq-cp2p-hrgf: SVG href attribute bypasses local-reference restriction in Loofah
• CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Credit

Found by maintainer Mike Dalessio during a security audit.

Summary

There is a possible cross-site scripting vulnerability in rails-html-sanitizer when the sanitizer is configured to allow an SVG reference element such as <use>. See related GHSA-9wjq-cp2p-hrgf in Loofah, whose SVG local-reference logic rails-html-sanitizer mirrors.

• Versions affected: >= 1.0.3, < 1.7.1
• Not affected: < 1.0.3
• Fixed versions: 1.7.1

Impact

Rails::HTML::PermitScrubber restricts SVG reference elements in the SVG_ALLOW_LOCAL_HREF collection to local, same-document references, but that restriction covered only the xlink:href attribute. Browsers also accept a plain href attribute per the SVG 2 spec, and it was not restricted, so those elements could reference arbitrary external documents. SVG <use> can load and render external SVG content by reference, and if the referenced document is same-origin and contains scripts, it could execute in the context of the sanitized document. <feImage> can load external images, which can be used for tracking.

Applications are impacted only when the allowed tags are overridden to include one of these SVG reference elements, for example <use> or <feImage>. The default allowed tags do not include these SVG elements, so applications using the default configuration are not affected.

Workarounds

Remove the SVG reference elements (such as use and feImage) from the overridden allowed tags. Applications using the default allowed tags are not affected.

References

• GHSA-9wjq-cp2p-hrgf: SVG href attribute bypasses local-reference restriction in Loofah
• CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Credit

Found by maintainer Mike Dalessio during a security audit.

Summary

There is a possible cross-site scripting vulnerability in rails-html-sanitizer when the sanitizer is configured to allow an SVG reference element such as <use>. See related GHSA-9wjq-cp2p-hrgf in Loofah, whose SVG local-reference logic rails-html-sanitizer mirrors.

• Versions affected: >= 1.0.3, < 1.7.1
• Not affected: < 1.0.3
• Fixed versions: 1.7.1

Impact

Rails::HTML::PermitScrubber restricts SVG reference elements in the SVG_ALLOW_LOCAL_HREF collection to local, same-document references, but that restriction covered only the xlink:href attribute. Browsers also accept a plain href attribute per the SVG 2 spec, and it was not restricted, so those elements could reference arbitrary external documents. SVG <use> can load and render external SVG content by reference, and if the referenced document is same-origin and contains scripts, it could execute in the context of the sanitized document. <feImage> can load external images, which can be used for tracking.

Applications are impacted only when the allowed tags are overridden to include one of these SVG reference elements, for example <use> or <feImage>. The default allowed tags do not include these SVG elements, so applications using the default configuration are not affected.

Workarounds

Remove the SVG reference elements (such as use and feImage) from the overridden allowed tags. Applications using the default allowed tags are not affected.

References

• GHSA-9wjq-cp2p-hrgf: SVG href attribute bypasses local-reference restriction in Loofah
• CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Credit

Found by maintainer Mike Dalessio during a security audit.

Summary

There is a possible cross-site scripting vulnerability in rails-html-sanitizer when the sanitizer is configured to allow an SVG reference element such as <use>. See related GHSA-9wjq-cp2p-hrgf in Loofah, whose SVG local-reference logic rails-html-sanitizer mirrors.

• Versions affected: >= 1.0.3, < 1.7.1
• Not affected: < 1.0.3
• Fixed versions: 1.7.1

Impact

Rails::HTML::PermitScrubber restricts SVG reference elements in the SVG_ALLOW_LOCAL_HREF collection to local, same-document references, but that restriction covered only the xlink:href attribute. Browsers also accept a plain href attribute per the SVG 2 spec, and it was not restricted, so those elements could reference arbitrary external documents. SVG <use> can load and render external SVG content by reference, and if the referenced document is same-origin and contains scripts, it could execute in the context of the sanitized document. <feImage> can load external images, which can be used for tracking.

Applications are impacted only when the allowed tags are overridden to include one of these SVG reference elements, for example <use> or <feImage>. The default allowed tags do not include these SVG elements, so applications using the default configuration are not affected.

Workarounds

Remove the SVG reference elements (such as use and feImage) from the overridden allowed tags. Applications using the default allowed tags are not affected.

References

• GHSA-9wjq-cp2p-hrgf: SVG href attribute bypasses local-reference restriction in Loofah
• CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Credit

Found by maintainer Mike Dalessio during a security audit.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::HTML::Sanitizer 1.6.0 when used with Rails >= 7.1.0.

• Versions affected: 1.6.0
• Not affected: < 1.6.0
• Fixed versions: 1.6.1

Impact

A possible XSS vulnerability with certain configurations of Rails::HTML::Sanitizer may allow an attacker to inject content if HTML5 sanitization is enabled and the application developer has overridden the sanitizer's allowed tags in the following way:

• the "noscript" element is explicitly allowed

Code is only impacted if Rails is configured to use HTML5 sanitization, please see documentation for config.action_view.sanitizer_vendor and config.action_text.sanitizer_vendor for more information on these configuration options.

The default configuration is to disallow all of these elements. Code is only impacted if allowed tags are being overridden. Applications may be doing this in a few different ways:

1. using application configuration to configure Action View sanitizers' allowed tags:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["noscript"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

2. using a :tags option to the Action View helper sanitize:

<%= sanitize @comment.body, tags: ["noscript"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

3. setting Rails::HTML5::SafeListSanitizer class attribute allowed_tags:

# class-level option
Rails::HTML5::SafeListSanitizer.allowed_tags = ["noscript"]

(note that this class may also be referenced as Rails::Html::SafeListSanitizer)

4. using a :tags options to the Rails::HTML5::SafeListSanitizer instance method sanitize:

# instance-level option
Rails::HTML5::SafeListSanitizer.new.sanitize(@article.body, tags: ["noscript"])

(note that this class may also be referenced as Rails::Html::SafeListSanitizer)

5. setting ActionText::ContentHelper module attribute allowed_tags:

ActionText::ContentHelper.allowed_tags = ["noscript"]

All users overriding the allowed tags by any of the above mechanisms to include "noscript" should either upgrade or use one of the workarounds.

Workarounds

Any one of the following actions will work around this issue:

• Remove "noscript" from the overridden allowed tags,
• Or, downgrade sanitization to HTML4 (see documentation for config.action_view.sanitizer_vendor and config.action_text.sanitizer_vendor for more information).

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• Original report: https://hackerone.com/reports/2509647

Credit

This vulnerability was responsibly reported by So Sakaguchi (mokusou) and taise.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::HTML::Sanitizer 1.6.0 when used with Rails >= 7.1.0.

• Versions affected: 1.6.0
• Not affected: < 1.6.0
• Fixed versions: 1.6.1

Impact

A possible XSS vulnerability with certain configurations of Rails::HTML::Sanitizer may allow an attacker to inject content if HTML5 sanitization is enabled and the application developer has overridden the sanitizer's allowed tags in the following way:

• the "style" element is explicitly allowed
• the "svg" or "math" element is not allowed

Code is only impacted if Rails is configured to use HTML5 sanitization, please see documentation for config.action_view.sanitizer_vendor and config.action_text.sanitizer_vendor for more information on these configuration options.

The default configuration is to disallow all of these elements. Code is only impacted if allowed tags are being overridden. Applications may be doing this in a few different ways:

1. using application configuration to configure Action View sanitizers' allowed tags:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["style"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

2. using a :tags option to the Action View helper sanitize:

<%= sanitize @comment.body, tags: ["style"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

3. setting Rails::HTML5::SafeListSanitizer class attribute allowed_tags:

# class-level option
Rails::HTML5::SafeListSanitizer.allowed_tags = ["style"]

(note that this class may also be referenced as Rails::Html::SafeListSanitizer)

4. using a :tags options to the Rails::HTML5::SafeListSanitizer instance method sanitize:

# instance-level option
Rails::HTML5::SafeListSanitizer.new.sanitize(@article.body, tags: ["style"])

(note that this class may also be referenced as Rails::Html::SafeListSanitizer)

5. setting ActionText::ContentHelper module attribute allowed_tags:

ActionText::ContentHelper.allowed_tags = ["style"]

All users overriding the allowed tags by any of the above mechanisms to include "style" and omit "svg" or "math" should either upgrade or use one of the workarounds.

Workarounds

Any one of the following actions will work around this issue:

• Remove "style" from the overridden allowed tags,
• Or, downgrade sanitization to HTML4 (see documentation for config.action_view.sanitizer_vendor and config.action_text.sanitizer_vendor for more information).

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• Original report: https://hackerone.com/reports/2519936

Credit

This vulnerability was responsibly reported by So Sakaguchi (mokusou) and taise.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::HTML::Sanitizer 1.6.0 when used with Rails >= 7.1.0.

• Versions affected: 1.6.0
• Not affected: < 1.6.0
• Fixed versions: 1.6.1

Impact

A possible XSS vulnerability with certain configurations of Rails::HTML::Sanitizer may allow an attacker to inject content if HTML5 sanitization is enabled and the application developer has overridden the sanitizer's allowed tags in the following way:

• the "math", "mtext", "table", and "style" elements are allowed
• and either "mglyph" or "malignmark" are allowed

Code is only impacted if Rails is configured to use HTML5 sanitization, please see documentation for config.action_view.sanitizer_vendor and config.action_text.sanitizer_vendor for more information on these configuration options.

The default configuration is to disallow all of these elements except for "table". Code is only impacted if allowed tags are being overridden. Applications may be doing this in a few different ways:

1. using application configuration to configure Action View sanitizers' allowed tags:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["math", "mtext", "table", "style", "mglyph"]
# or
config.action_view.sanitized_allowed_tags = ["math", "mtext", "table", "style", "malignmark"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

2. using a :tags option to the Action View helper sanitize:

<%= sanitize @comment.body, tags: ["math", "mtext", "table", "style", "mglyph"] %>
<%# or %>
<%= sanitize @comment.body, tags: ["math", "mtext", "table", "style", "malignmark"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

3. setting Rails::HTML5::SafeListSanitizer class attribute allowed_tags:

# class-level option
Rails::HTML5::SafeListSanitizer.allowed_tags = ["math", "mtext", "table", "style", "mglyph"]
# or
Rails::HTML5::SafeListSanitizer.allowed_tags = ["math", "mtext", "table", "style", "malignmark"]

(note that this class may also be referenced as Rails::Html::SafeListSanitizer)

4. using a :tags options to the Rails::HTML5::SafeListSanitizer instance method sanitize:

# instance-level option
Rails::HTML5::SafeListSanitizer.new.sanitize(@article.body, tags: ["math", "mtext", "table", "style", "mglyph"])
# or
Rails::HTML5::SafeListSanitizer.new.sanitize(@article.body, tags: ["math", "mtext", "table", "style", "malignmark"])

(note that this class may also be referenced as Rails::Html::SafeListSanitizer)

5. setting ActionText::ContentHelper module attribute allowed_tags:

ActionText::ContentHelper.allowed_tags = ["math", "mtext", "table", "style", "mglyph"]
# or
ActionText::ContentHelper.allowed_tags = ["math", "mtext", "table", "style", "malignmark"]

All users overriding the allowed tags by any of the above mechanisms to include ("math" and "mtext" and "table" and "style" and ("mglyph" or "malignmark")) should either upgrade or use one of the workarounds.

Workarounds

Any one of the following actions will work around this issue:

• Remove "mglyph" and "malignmark" from the overridden allowed tags,
• Or, downgrade sanitization to HTML4 (see documentation for config.action_view.sanitizer_vendor and config.action_text.sanitizer_vendor for more information).

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• Original report: https://hackerone.com/reports/2519936

Credit

This vulnerability was responsibly reported by So Sakaguchi (mokusou) and taise.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::HTML::Sanitizer 1.6.0 when used with Rails >= 7.1.0.

• Versions affected: 1.6.0
• Not affected: < 1.6.0
• Fixed versions: 1.6.1

Impact

A possible XSS vulnerability with certain configurations of Rails::HTML::Sanitizer may allow an attacker to inject content if HTML5 sanitization is enabled and the application developer has overridden the sanitizer's allowed tags in the following way:

• the "math" and "style" elements are both explicitly allowed

Code is only impacted if Rails is configured to use HTML5 sanitization, please see documentation for config.action_view.sanitizer_vendor and config.action_text.sanitizer_vendor for more information on these configuration options.

The default configuration is to disallow these elements. Code is only impacted if allowed tags are being overridden. Applications may be doing this in a few different ways:

1. using application configuration to configure Action View sanitizers' allowed tags:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["math", "style"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

2. using a :tags option to the Action View helper sanitize:

<%= sanitize @comment.body, tags: ["math", "style"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

3. setting Rails::HTML5::SafeListSanitizer class attribute allowed_tags:

# class-level option
Rails::HTML5::SafeListSanitizer.allowed_tags = ["math", "style"]

(note that this class may also be referenced as Rails::Html::SafeListSanitizer)

4. using a :tags options to the Rails::HTML5::SafeListSanitizer instance method sanitize:

# instance-level option
Rails::HTML5::SafeListSanitizer.new.sanitize(@article.body, tags: ["math", "style"])

(note that this class may also be referenced as Rails::Html::SafeListSanitizer)

5. setting ActionText::ContentHelper module attribute allowed_tags:

ActionText::ContentHelper.allowed_tags = ["math", "style"]

All users overriding the allowed tags by any of the above mechanisms to include both "math" and "style" should either upgrade or use one of the workarounds.

Workarounds

Any one of the following actions will work around this issue:

• Remove "math" or "style" from the overridden allowed tags,
• Or, downgrade sanitization to HTML4 (see documentation for config.action_view.sanitizer_vendor and config.action_text.sanitizer_vendor for more information).

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• Original report: https://hackerone.com/reports/2519941

Credit

This vulnerability was responsibly reported by So Sakaguchi (mokusou) and taise.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::HTML::Sanitizer 1.6.0 when used with Rails >= 7.1.0 and Nokogiri < 1.15.7, or 1.16.x < 1.16.8.

• Versions affected: 1.6.0
• Not affected: < 1.6.0
• Fixed versions: 1.6.1

Please note that the fix in v1.6.1 is to update the dependency on Nokogiri to 1.15.7 or >= 1.16.8.

Impact

A possible XSS vulnerability with certain configurations of Rails::HTML::Sanitizer may allow an attacker to inject content if HTML5 sanitization is enabled and the application developer has overridden the sanitizer's allowed tags in either of the following ways:

• allow both "math" and "style" elements
• or allow both "svg" and "style" elements

Code is only impacted if Rails is configured to use HTML5 sanitization, please see documentation for config.action_view.sanitizer_vendor and config.action_text.sanitizer_vendor for more information on these configuration options.

Code is only impacted if allowed tags are being overridden. Applications may be doing this in a few different ways:

1. using application configuration to configure Action View sanitizers' allowed tags:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["math", "style"]
# or
config.action_view.sanitized_allowed_tags = ["svg", "style"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

2. using a :tags option to the Action View helper sanitize:

<%= sanitize @comment.body, tags: ["math", "style"] %>
<%# or %>
<%= sanitize @comment.body, tags: ["svg", "style"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

3. setting Rails::HTML5::SafeListSanitizer class attribute allowed_tags:

# class-level option
Rails::HTML5::SafeListSanitizer.allowed_tags = ["math", "style"]
# or
Rails::HTML5::SafeListSanitizer.allowed_tags = ["svg", "style"]

(note that this class may also be referenced as Rails::Html::SafeListSanitizer)

4. using a :tags options to the Rails::HTML5::SafeListSanitizer instance method sanitize:

# instance-level option
Rails::HTML5::SafeListSanitizer.new.sanitize(@article.body, tags: ["math", "style"])
# or
Rails::HTML5::SafeListSanitizer.new.sanitize(@article.body, tags: ["svg", "style"])

(note that this class may also be referenced as Rails::Html::SafeListSanitizer)

5. setting ActionText::ContentHelper module attribute allowed_tags:

ActionText::ContentHelper.allowed_tags = ["math", "style"]
# or
ActionText::ContentHelper.allowed_tags = ["svg", "style"]

All users overriding the allowed tags by any of the above mechanisms to include (("math" or "svg") and "style") should either upgrade or use one of the workarounds.

Workarounds

Any one of the following actions will work around this issue:

• Remove "style" from the overridden allowed tags,
• Or, remove "math" and "svg" from the overridden allowed tags,
• Or, downgrade sanitization to HTML4 (see documentation for config.action_view.sanitizer_vendor and config.action_text.sanitizer_vendor for more information)
• Or, independently upgrade Nokogiri to v1.15.7 or >= 1.16.8.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• Original report: https://hackerone.com/reports/2503220

Credit

This vulnerability was responsibly reported by So Sakaguchi (mokusou) and taise.

Summary

There is a possible cross-site scripting vulnerability in rails-html-sanitizer when the sanitizer is configured to allow an SVG reference element such as <use>. See related GHSA-9wjq-cp2p-hrgf in Loofah, whose SVG local-reference logic rails-html-sanitizer mirrors.

• Versions affected: >= 1.0.3, < 1.7.1
• Not affected: < 1.0.3
• Fixed versions: 1.7.1

Impact

Rails::HTML::PermitScrubber restricts SVG reference elements in the SVG_ALLOW_LOCAL_HREF collection to local, same-document references, but that restriction covered only the xlink:href attribute. Browsers also accept a plain href attribute per the SVG 2 spec, and it was not restricted, so those elements could reference arbitrary external documents. SVG <use> can load and render external SVG content by reference, and if the referenced document is same-origin and contains scripts, it could execute in the context of the sanitized document. <feImage> can load external images, which can be used for tracking.

Applications are impacted only when the allowed tags are overridden to include one of these SVG reference elements, for example <use> or <feImage>. The default allowed tags do not include these SVG elements, so applications using the default configuration are not affected.

Workarounds

Remove the SVG reference elements (such as use and feImage) from the overridden allowed tags. Applications using the default allowed tags are not affected.

References

• GHSA-9wjq-cp2p-hrgf: SVG href attribute bypasses local-reference restriction in Loofah
• CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Credit

Found by maintainer Mike Dalessio during a security audit.

Summary

There is a possible cross-site scripting vulnerability in rails-html-sanitizer when the sanitizer is configured to allow an SVG reference element such as <use>. See related GHSA-9wjq-cp2p-hrgf in Loofah, whose SVG local-reference logic rails-html-sanitizer mirrors.

• Versions affected: >= 1.0.3, < 1.7.1
• Not affected: < 1.0.3
• Fixed versions: 1.7.1

Impact

Rails::HTML::PermitScrubber restricts SVG reference elements in the SVG_ALLOW_LOCAL_HREF collection to local, same-document references, but that restriction covered only the xlink:href attribute. Browsers also accept a plain href attribute per the SVG 2 spec, and it was not restricted, so those elements could reference arbitrary external documents. SVG <use> can load and render external SVG content by reference, and if the referenced document is same-origin and contains scripts, it could execute in the context of the sanitized document. <feImage> can load external images, which can be used for tracking.

Applications are impacted only when the allowed tags are overridden to include one of these SVG reference elements, for example <use> or <feImage>. The default allowed tags do not include these SVG elements, so applications using the default configuration are not affected.

Workarounds

Remove the SVG reference elements (such as use and feImage) from the overridden allowed tags. Applications using the default allowed tags are not affected.

References

• GHSA-9wjq-cp2p-hrgf: SVG href attribute bypasses local-reference restriction in Loofah
• CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Credit

Found by maintainer Mike Dalessio during a security audit.

Summary

There is a possible cross-site scripting vulnerability in rails-html-sanitizer when the sanitizer is configured to allow an SVG reference element such as <use>. See related GHSA-9wjq-cp2p-hrgf in Loofah, whose SVG local-reference logic rails-html-sanitizer mirrors.

• Versions affected: >= 1.0.3, < 1.7.1
• Not affected: < 1.0.3
• Fixed versions: 1.7.1

Impact

Rails::HTML::PermitScrubber restricts SVG reference elements in the SVG_ALLOW_LOCAL_HREF collection to local, same-document references, but that restriction covered only the xlink:href attribute. Browsers also accept a plain href attribute per the SVG 2 spec, and it was not restricted, so those elements could reference arbitrary external documents. SVG <use> can load and render external SVG content by reference, and if the referenced document is same-origin and contains scripts, it could execute in the context of the sanitized document. <feImage> can load external images, which can be used for tracking.

Applications are impacted only when the allowed tags are overridden to include one of these SVG reference elements, for example <use> or <feImage>. The default allowed tags do not include these SVG elements, so applications using the default configuration are not affected.

Workarounds

Remove the SVG reference elements (such as use and feImage) from the overridden allowed tags. Applications using the default allowed tags are not affected.

References

• GHSA-9wjq-cp2p-hrgf: SVG href attribute bypasses local-reference restriction in Loofah
• CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Credit

Found by maintainer Mike Dalessio during a security audit.

Summary

There is a possible cross-site scripting vulnerability in rails-html-sanitizer when the sanitizer is configured to allow an SVG reference element such as <use>. See related GHSA-9wjq-cp2p-hrgf in Loofah, whose SVG local-reference logic rails-html-sanitizer mirrors.

• Versions affected: >= 1.0.3, < 1.7.1
• Not affected: < 1.0.3
• Fixed versions: 1.7.1

Impact

Rails::HTML::PermitScrubber restricts SVG reference elements in the SVG_ALLOW_LOCAL_HREF collection to local, same-document references, but that restriction covered only the xlink:href attribute. Browsers also accept a plain href attribute per the SVG 2 spec, and it was not restricted, so those elements could reference arbitrary external documents. SVG <use> can load and render external SVG content by reference, and if the referenced document is same-origin and contains scripts, it could execute in the context of the sanitized document. <feImage> can load external images, which can be used for tracking.

Applications are impacted only when the allowed tags are overridden to include one of these SVG reference elements, for example <use> or <feImage>. The default allowed tags do not include these SVG elements, so applications using the default configuration are not affected.

Workarounds

Remove the SVG reference elements (such as use and feImage) from the overridden allowed tags. Applications using the default allowed tags are not affected.

References

• GHSA-9wjq-cp2p-hrgf: SVG href attribute bypasses local-reference restriction in Loofah
• CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Credit

Found by maintainer Mike Dalessio during a security audit.

Summary

There is a possible cross-site scripting vulnerability in rails-html-sanitizer when the sanitizer is configured to allow an SVG reference element such as <use>. See related GHSA-9wjq-cp2p-hrgf in Loofah, whose SVG local-reference logic rails-html-sanitizer mirrors.

• Versions affected: >= 1.0.3, < 1.7.1
• Not affected: < 1.0.3
• Fixed versions: 1.7.1

Impact

Rails::HTML::PermitScrubber restricts SVG reference elements in the SVG_ALLOW_LOCAL_HREF collection to local, same-document references, but that restriction covered only the xlink:href attribute. Browsers also accept a plain href attribute per the SVG 2 spec, and it was not restricted, so those elements could reference arbitrary external documents. SVG <use> can load and render external SVG content by reference, and if the referenced document is same-origin and contains scripts, it could execute in the context of the sanitized document. <feImage> can load external images, which can be used for tracking.

Applications are impacted only when the allowed tags are overridden to include one of these SVG reference elements, for example <use> or <feImage>. The default allowed tags do not include these SVG elements, so applications using the default configuration are not affected.

Workarounds

Remove the SVG reference elements (such as use and feImage) from the overridden allowed tags. Applications using the default allowed tags are not affected.

References

• GHSA-9wjq-cp2p-hrgf: SVG href attribute bypasses local-reference restriction in Loofah
• CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Credit

Found by maintainer Mike Dalessio during a security audit.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer. This is due to an incomplete fix of CVE-2022-32209.

• Versions affected: ALL
• Not affected: NONE
• Fixed versions: 1.4.4

Impact

A possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer may allow an attacker to inject content if the application developer has overridden the sanitizer's allowed tags to allow both "select" and "style" elements.

Code is only impacted if allowed tags are being overridden using either of the following two mechanisms:

1. Using the Rails configuration config.action_view.sanitized_allow_tags=:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["select", "style"]

(see https://guides.rubyonrails.org/configuring.html#configuring-action-view)

2. Using the class method Rails::Html::SafeListSanitizer.allowed_tags=:

# class-level option
Rails::Html::SafeListSanitizer.allowed_tags = ["select", "style"]

All users overriding the allowed tags by either of the above mechanisms to include both "select" and "style" should either upgrade or use one of the workarounds immediately.

NOTE: Code is not impacted if allowed tags are overridden using either of the following mechanisms:

• the :tags option to the Action View helper method sanitize.
• the :tags option to the instance method SafeListSanitizer#sanitize.

Workarounds

Remove either "select" or "style" from the overridden allowed tags.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-32209
• https://hackerone.com/reports/1654310

Credit

This vulnerability was responsibly reported by Dominic Breuker.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer.

• Versions affected: ALL
• Not affected: NONE
• Fixed versions: 1.4.4

Impact

A possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer may allow an attacker to inject content if the application developer has overridden the sanitizer's allowed tags in either of the following ways:

• allow both "math" and "style" elements,
• or allow both "svg" and "style" elements

Code is only impacted if allowed tags are being overridden. Applications may be doing this in four different ways:

1. using application configuration:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["math", "style"]
# or
config.action_view.sanitized_allowed_tags = ["svg", "style"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

2. using a :tags option to the Action View helper sanitize:

<%= sanitize @comment.body, tags: ["math", "style"] %>
<%# or %>
<%= sanitize @comment.body, tags: ["svg", "style"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

3. using Rails::Html::SafeListSanitizer class method allowed_tags=:

# class-level option
Rails::Html::SafeListSanitizer.allowed_tags = ["math", "style"]
# or
Rails::Html::SafeListSanitizer.allowed_tags = ["svg", "style"]

4. using a :tags options to the Rails::Html::SafeListSanitizer instance method sanitize:

# instance-level option
Rails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["math", "style"])
# or
Rails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["svg", "style"])

All users overriding the allowed tags by any of the above mechanisms to include (("math" or "svg") and "style") should either upgrade or use one of the workarounds immediately.

Workarounds

Remove "style" from the overridden allowed tags, or remove "math" and "svg" from the overridden allowed tags.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• https://hackerone.com/reports/1656627

Credit

This vulnerability was responsibly reported by Dominic Breuker.

Summary

rails-html-sanitizer >= 1.0.3, < 1.4.4 is vulnerable to cross-site scripting via data URIs when used in combination with Loofah >= 2.1.0.

Mitigation

Upgrade to rails-html-sanitizer >= 1.4.4.

Severity

The maintainers have evaluated this as Medium Severity 6.1.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• SVG MIME Type (image/svg+xml) is misleading to developers · Issue #266 · w3c/svgwg
• https://github.com/rails/rails-html-sanitizer/issues/135
• https://hackerone.com/reports/1694173

Credit

This vulnerability was independently reported by Maciej Piechota (@haqpl) and Mrinmoy Das (@goromlagche).

Summary

Certain configurations of rails-html-sanitizer < 1.4.4 use an inefficient regular expression that is susceptible to excessive backtracking when attempting to sanitize certain SVG attributes. This may lead to a denial of service through CPU resource consumption.

Mitigation

Upgrade to rails-html-sanitizer >= 1.4.4.

Severity

The maintainers have evaluated this as High Severity 7.5 (CVSS3.1).

References

• CWE - CWE-1333: Inefficient Regular Expression Complexity (4.9)
• https://hackerone.com/reports/1684163

Credit

This vulnerability was responsibly reported by @ooooooo-q (https://github.com/ooooooo-q).

Summary

There is a possible cross-site scripting vulnerability in rails-html-sanitizer when the sanitizer is configured to allow an SVG reference element such as <use>. See related GHSA-9wjq-cp2p-hrgf in Loofah, whose SVG local-reference logic rails-html-sanitizer mirrors.

• Versions affected: >= 1.0.3, < 1.7.1
• Not affected: < 1.0.3
• Fixed versions: 1.7.1

Impact

Rails::HTML::PermitScrubber restricts SVG reference elements in the SVG_ALLOW_LOCAL_HREF collection to local, same-document references, but that restriction covered only the xlink:href attribute. Browsers also accept a plain href attribute per the SVG 2 spec, and it was not restricted, so those elements could reference arbitrary external documents. SVG <use> can load and render external SVG content by reference, and if the referenced document is same-origin and contains scripts, it could execute in the context of the sanitized document. <feImage> can load external images, which can be used for tracking.

Applications are impacted only when the allowed tags are overridden to include one of these SVG reference elements, for example <use> or <feImage>. The default allowed tags do not include these SVG elements, so applications using the default configuration are not affected.

Workarounds

Remove the SVG reference elements (such as use and feImage) from the overridden allowed tags. Applications using the default allowed tags are not affected.

References

• GHSA-9wjq-cp2p-hrgf: SVG href attribute bypasses local-reference restriction in Loofah
• CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Credit

Found by maintainer Mike Dalessio during a security audit.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer. This is due to an incomplete fix of CVE-2022-32209.

• Versions affected: ALL
• Not affected: NONE
• Fixed versions: 1.4.4

Impact

A possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer may allow an attacker to inject content if the application developer has overridden the sanitizer's allowed tags to allow both "select" and "style" elements.

Code is only impacted if allowed tags are being overridden using either of the following two mechanisms:

1. Using the Rails configuration config.action_view.sanitized_allow_tags=:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["select", "style"]

(see https://guides.rubyonrails.org/configuring.html#configuring-action-view)

2. Using the class method Rails::Html::SafeListSanitizer.allowed_tags=:

# class-level option
Rails::Html::SafeListSanitizer.allowed_tags = ["select", "style"]

All users overriding the allowed tags by either of the above mechanisms to include both "select" and "style" should either upgrade or use one of the workarounds immediately.

NOTE: Code is not impacted if allowed tags are overridden using either of the following mechanisms:

• the :tags option to the Action View helper method sanitize.
• the :tags option to the instance method SafeListSanitizer#sanitize.

Workarounds

Remove either "select" or "style" from the overridden allowed tags.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-32209
• https://hackerone.com/reports/1654310

Credit

This vulnerability was responsibly reported by Dominic Breuker.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer.

• Versions affected: ALL
• Not affected: NONE
• Fixed versions: 1.4.4

Impact

A possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer may allow an attacker to inject content if the application developer has overridden the sanitizer's allowed tags in either of the following ways:

• allow both "math" and "style" elements,
• or allow both "svg" and "style" elements

Code is only impacted if allowed tags are being overridden. Applications may be doing this in four different ways:

1. using application configuration:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["math", "style"]
# or
config.action_view.sanitized_allowed_tags = ["svg", "style"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

2. using a :tags option to the Action View helper sanitize:

<%= sanitize @comment.body, tags: ["math", "style"] %>
<%# or %>
<%= sanitize @comment.body, tags: ["svg", "style"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

3. using Rails::Html::SafeListSanitizer class method allowed_tags=:

# class-level option
Rails::Html::SafeListSanitizer.allowed_tags = ["math", "style"]
# or
Rails::Html::SafeListSanitizer.allowed_tags = ["svg", "style"]

4. using a :tags options to the Rails::Html::SafeListSanitizer instance method sanitize:

# instance-level option
Rails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["math", "style"])
# or
Rails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["svg", "style"])

All users overriding the allowed tags by any of the above mechanisms to include (("math" or "svg") and "style") should either upgrade or use one of the workarounds immediately.

Workarounds

Remove "style" from the overridden allowed tags, or remove "math" and "svg" from the overridden allowed tags.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• https://hackerone.com/reports/1656627

Credit

This vulnerability was responsibly reported by Dominic Breuker.

Summary

rails-html-sanitizer >= 1.0.3, < 1.4.4 is vulnerable to cross-site scripting via data URIs when used in combination with Loofah >= 2.1.0.

Mitigation

Upgrade to rails-html-sanitizer >= 1.4.4.

Severity

The maintainers have evaluated this as Medium Severity 6.1.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• SVG MIME Type (image/svg+xml) is misleading to developers · Issue #266 · w3c/svgwg
• https://github.com/rails/rails-html-sanitizer/issues/135
• https://hackerone.com/reports/1694173

Credit

This vulnerability was independently reported by Maciej Piechota (@haqpl) and Mrinmoy Das (@goromlagche).

Summary

Certain configurations of rails-html-sanitizer < 1.4.4 use an inefficient regular expression that is susceptible to excessive backtracking when attempting to sanitize certain SVG attributes. This may lead to a denial of service through CPU resource consumption.

Mitigation

Upgrade to rails-html-sanitizer >= 1.4.4.

Severity

The maintainers have evaluated this as High Severity 7.5 (CVSS3.1).

References

• CWE - CWE-1333: Inefficient Regular Expression Complexity (4.9)
• https://hackerone.com/reports/1684163

Credit

This vulnerability was responsibly reported by @ooooooo-q (https://github.com/ooooooo-q).

Versions of Rails::Html::Sanitizer prior to version 1.4.3 are vulnerable to XSS with certain configurations of Rails::Html::Sanitizer which allows an attacker to inject content when the application developer has overridden the sanitizer's allowed tags to allow both select and style elements. Code is only impacted if allowed tags are being overridden.

This may be done via application configuration: ruby# In config/application.rbconfig.action_view.sanitized_allowed_tags = ["select", "style"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

Or it may be done with a :tags option to the Action View helper sanitize: <%= sanitize @comment.body, tags: ["select", "style"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

It may also be done with Rails::Html::SafeListSanitizer directly: ruby# class-level optionRails::Html::SafeListSanitizer.allowed_tags = ["select", "style"] or with ruby# instance-level optionRails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["select", "style"])

All users overriding the allowed tags by any of the above mechanisms to include both "select" and "style" are recommended to upgrade immediately. A workaround for this issue can be applied by removing either select or style from the overridden allowed tags.

Summary

There is a possible cross-site scripting vulnerability in rails-html-sanitizer when the sanitizer is configured to allow an SVG reference element such as <use>. See related GHSA-9wjq-cp2p-hrgf in Loofah, whose SVG local-reference logic rails-html-sanitizer mirrors.

• Versions affected: >= 1.0.3, < 1.7.1
• Not affected: < 1.0.3
• Fixed versions: 1.7.1

Impact

Rails::HTML::PermitScrubber restricts SVG reference elements in the SVG_ALLOW_LOCAL_HREF collection to local, same-document references, but that restriction covered only the xlink:href attribute. Browsers also accept a plain href attribute per the SVG 2 spec, and it was not restricted, so those elements could reference arbitrary external documents. SVG <use> can load and render external SVG content by reference, and if the referenced document is same-origin and contains scripts, it could execute in the context of the sanitized document. <feImage> can load external images, which can be used for tracking.

Applications are impacted only when the allowed tags are overridden to include one of these SVG reference elements, for example <use> or <feImage>. The default allowed tags do not include these SVG elements, so applications using the default configuration are not affected.

Workarounds

Remove the SVG reference elements (such as use and feImage) from the overridden allowed tags. Applications using the default allowed tags are not affected.

References

• GHSA-9wjq-cp2p-hrgf: SVG href attribute bypasses local-reference restriction in Loofah
• CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Credit

Found by maintainer Mike Dalessio during a security audit.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer. This is due to an incomplete fix of CVE-2022-32209.

• Versions affected: ALL
• Not affected: NONE
• Fixed versions: 1.4.4

Impact

A possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer may allow an attacker to inject content if the application developer has overridden the sanitizer's allowed tags to allow both "select" and "style" elements.

Code is only impacted if allowed tags are being overridden using either of the following two mechanisms:

1. Using the Rails configuration config.action_view.sanitized_allow_tags=:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["select", "style"]

(see https://guides.rubyonrails.org/configuring.html#configuring-action-view)

2. Using the class method Rails::Html::SafeListSanitizer.allowed_tags=:

# class-level option
Rails::Html::SafeListSanitizer.allowed_tags = ["select", "style"]

All users overriding the allowed tags by either of the above mechanisms to include both "select" and "style" should either upgrade or use one of the workarounds immediately.

NOTE: Code is not impacted if allowed tags are overridden using either of the following mechanisms:

• the :tags option to the Action View helper method sanitize.
• the :tags option to the instance method SafeListSanitizer#sanitize.

Workarounds

Remove either "select" or "style" from the overridden allowed tags.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-32209
• https://hackerone.com/reports/1654310

Credit

This vulnerability was responsibly reported by Dominic Breuker.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer.

• Versions affected: ALL
• Not affected: NONE
• Fixed versions: 1.4.4

Impact

A possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer may allow an attacker to inject content if the application developer has overridden the sanitizer's allowed tags in either of the following ways:

• allow both "math" and "style" elements,
• or allow both "svg" and "style" elements

Code is only impacted if allowed tags are being overridden. Applications may be doing this in four different ways:

1. using application configuration:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["math", "style"]
# or
config.action_view.sanitized_allowed_tags = ["svg", "style"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

2. using a :tags option to the Action View helper sanitize:

<%= sanitize @comment.body, tags: ["math", "style"] %>
<%# or %>
<%= sanitize @comment.body, tags: ["svg", "style"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

3. using Rails::Html::SafeListSanitizer class method allowed_tags=:

# class-level option
Rails::Html::SafeListSanitizer.allowed_tags = ["math", "style"]
# or
Rails::Html::SafeListSanitizer.allowed_tags = ["svg", "style"]

4. using a :tags options to the Rails::Html::SafeListSanitizer instance method sanitize:

# instance-level option
Rails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["math", "style"])
# or
Rails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["svg", "style"])

All users overriding the allowed tags by any of the above mechanisms to include (("math" or "svg") and "style") should either upgrade or use one of the workarounds immediately.

Workarounds

Remove "style" from the overridden allowed tags, or remove "math" and "svg" from the overridden allowed tags.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• https://hackerone.com/reports/1656627

Credit

This vulnerability was responsibly reported by Dominic Breuker.

Summary

rails-html-sanitizer >= 1.0.3, < 1.4.4 is vulnerable to cross-site scripting via data URIs when used in combination with Loofah >= 2.1.0.

Mitigation

Upgrade to rails-html-sanitizer >= 1.4.4.

Severity

The maintainers have evaluated this as Medium Severity 6.1.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• SVG MIME Type (image/svg+xml) is misleading to developers · Issue #266 · w3c/svgwg
• https://github.com/rails/rails-html-sanitizer/issues/135
• https://hackerone.com/reports/1694173

Credit

This vulnerability was independently reported by Maciej Piechota (@haqpl) and Mrinmoy Das (@goromlagche).

Summary

Certain configurations of rails-html-sanitizer < 1.4.4 use an inefficient regular expression that is susceptible to excessive backtracking when attempting to sanitize certain SVG attributes. This may lead to a denial of service through CPU resource consumption.

Mitigation

Upgrade to rails-html-sanitizer >= 1.4.4.

Severity

The maintainers have evaluated this as High Severity 7.5 (CVSS3.1).

References

• CWE - CWE-1333: Inefficient Regular Expression Complexity (4.9)
• https://hackerone.com/reports/1684163

Credit

This vulnerability was responsibly reported by @ooooooo-q (https://github.com/ooooooo-q).

Versions of Rails::Html::Sanitizer prior to version 1.4.3 are vulnerable to XSS with certain configurations of Rails::Html::Sanitizer which allows an attacker to inject content when the application developer has overridden the sanitizer's allowed tags to allow both select and style elements. Code is only impacted if allowed tags are being overridden.

This may be done via application configuration: ruby# In config/application.rbconfig.action_view.sanitized_allowed_tags = ["select", "style"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

Or it may be done with a :tags option to the Action View helper sanitize: <%= sanitize @comment.body, tags: ["select", "style"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

It may also be done with Rails::Html::SafeListSanitizer directly: ruby# class-level optionRails::Html::SafeListSanitizer.allowed_tags = ["select", "style"] or with ruby# instance-level optionRails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["select", "style"])

All users overriding the allowed tags by any of the above mechanisms to include both "select" and "style" are recommended to upgrade immediately. A workaround for this issue can be applied by removing either select or style from the overridden allowed tags.

Summary

There is a possible cross-site scripting vulnerability in rails-html-sanitizer when the sanitizer is configured to allow an SVG reference element such as <use>. See related GHSA-9wjq-cp2p-hrgf in Loofah, whose SVG local-reference logic rails-html-sanitizer mirrors.

• Versions affected: >= 1.0.3, < 1.7.1
• Not affected: < 1.0.3
• Fixed versions: 1.7.1

Impact

Rails::HTML::PermitScrubber restricts SVG reference elements in the SVG_ALLOW_LOCAL_HREF collection to local, same-document references, but that restriction covered only the xlink:href attribute. Browsers also accept a plain href attribute per the SVG 2 spec, and it was not restricted, so those elements could reference arbitrary external documents. SVG <use> can load and render external SVG content by reference, and if the referenced document is same-origin and contains scripts, it could execute in the context of the sanitized document. <feImage> can load external images, which can be used for tracking.

Applications are impacted only when the allowed tags are overridden to include one of these SVG reference elements, for example <use> or <feImage>. The default allowed tags do not include these SVG elements, so applications using the default configuration are not affected.

Workarounds

Remove the SVG reference elements (such as use and feImage) from the overridden allowed tags. Applications using the default allowed tags are not affected.

References

• GHSA-9wjq-cp2p-hrgf: SVG href attribute bypasses local-reference restriction in Loofah
• CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Credit

Found by maintainer Mike Dalessio during a security audit.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer. This is due to an incomplete fix of CVE-2022-32209.

• Versions affected: ALL
• Not affected: NONE
• Fixed versions: 1.4.4

Impact

A possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer may allow an attacker to inject content if the application developer has overridden the sanitizer's allowed tags to allow both "select" and "style" elements.

Code is only impacted if allowed tags are being overridden using either of the following two mechanisms:

1. Using the Rails configuration config.action_view.sanitized_allow_tags=:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["select", "style"]

(see https://guides.rubyonrails.org/configuring.html#configuring-action-view)

2. Using the class method Rails::Html::SafeListSanitizer.allowed_tags=:

# class-level option
Rails::Html::SafeListSanitizer.allowed_tags = ["select", "style"]

All users overriding the allowed tags by either of the above mechanisms to include both "select" and "style" should either upgrade or use one of the workarounds immediately.

NOTE: Code is not impacted if allowed tags are overridden using either of the following mechanisms:

• the :tags option to the Action View helper method sanitize.
• the :tags option to the instance method SafeListSanitizer#sanitize.

Workarounds

Remove either "select" or "style" from the overridden allowed tags.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-32209
• https://hackerone.com/reports/1654310

Credit

This vulnerability was responsibly reported by Dominic Breuker.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer.

• Versions affected: ALL
• Not affected: NONE
• Fixed versions: 1.4.4

Impact

A possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer may allow an attacker to inject content if the application developer has overridden the sanitizer's allowed tags in either of the following ways:

• allow both "math" and "style" elements,
• or allow both "svg" and "style" elements

Code is only impacted if allowed tags are being overridden. Applications may be doing this in four different ways:

1. using application configuration:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["math", "style"]
# or
config.action_view.sanitized_allowed_tags = ["svg", "style"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

2. using a :tags option to the Action View helper sanitize:

<%= sanitize @comment.body, tags: ["math", "style"] %>
<%# or %>
<%= sanitize @comment.body, tags: ["svg", "style"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

3. using Rails::Html::SafeListSanitizer class method allowed_tags=:

# class-level option
Rails::Html::SafeListSanitizer.allowed_tags = ["math", "style"]
# or
Rails::Html::SafeListSanitizer.allowed_tags = ["svg", "style"]

4. using a :tags options to the Rails::Html::SafeListSanitizer instance method sanitize:

# instance-level option
Rails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["math", "style"])
# or
Rails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["svg", "style"])

All users overriding the allowed tags by any of the above mechanisms to include (("math" or "svg") and "style") should either upgrade or use one of the workarounds immediately.

Workarounds

Remove "style" from the overridden allowed tags, or remove "math" and "svg" from the overridden allowed tags.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• https://hackerone.com/reports/1656627

Credit

This vulnerability was responsibly reported by Dominic Breuker.

Summary

rails-html-sanitizer >= 1.0.3, < 1.4.4 is vulnerable to cross-site scripting via data URIs when used in combination with Loofah >= 2.1.0.

Mitigation

Upgrade to rails-html-sanitizer >= 1.4.4.

Severity

The maintainers have evaluated this as Medium Severity 6.1.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• SVG MIME Type (image/svg+xml) is misleading to developers · Issue #266 · w3c/svgwg
• https://github.com/rails/rails-html-sanitizer/issues/135
• https://hackerone.com/reports/1694173

Credit

This vulnerability was independently reported by Maciej Piechota (@haqpl) and Mrinmoy Das (@goromlagche).

Summary

Certain configurations of rails-html-sanitizer < 1.4.4 use an inefficient regular expression that is susceptible to excessive backtracking when attempting to sanitize certain SVG attributes. This may lead to a denial of service through CPU resource consumption.

Mitigation

Upgrade to rails-html-sanitizer >= 1.4.4.

Severity

The maintainers have evaluated this as High Severity 7.5 (CVSS3.1).

References

• CWE - CWE-1333: Inefficient Regular Expression Complexity (4.9)
• https://hackerone.com/reports/1684163

Credit

This vulnerability was responsibly reported by @ooooooo-q (https://github.com/ooooooo-q).

Versions of Rails::Html::Sanitizer prior to version 1.4.3 are vulnerable to XSS with certain configurations of Rails::Html::Sanitizer which allows an attacker to inject content when the application developer has overridden the sanitizer's allowed tags to allow both select and style elements. Code is only impacted if allowed tags are being overridden.

This may be done via application configuration: ruby# In config/application.rbconfig.action_view.sanitized_allowed_tags = ["select", "style"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

Or it may be done with a :tags option to the Action View helper sanitize: <%= sanitize @comment.body, tags: ["select", "style"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

It may also be done with Rails::Html::SafeListSanitizer directly: ruby# class-level optionRails::Html::SafeListSanitizer.allowed_tags = ["select", "style"] or with ruby# instance-level optionRails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["select", "style"])

All users overriding the allowed tags by any of the above mechanisms to include both "select" and "style" are recommended to upgrade immediately. A workaround for this issue can be applied by removing either select or style from the overridden allowed tags.

Summary

There is a possible cross-site scripting vulnerability in rails-html-sanitizer when the sanitizer is configured to allow an SVG reference element such as <use>. See related GHSA-9wjq-cp2p-hrgf in Loofah, whose SVG local-reference logic rails-html-sanitizer mirrors.

• Versions affected: >= 1.0.3, < 1.7.1
• Not affected: < 1.0.3
• Fixed versions: 1.7.1

Impact

Rails::HTML::PermitScrubber restricts SVG reference elements in the SVG_ALLOW_LOCAL_HREF collection to local, same-document references, but that restriction covered only the xlink:href attribute. Browsers also accept a plain href attribute per the SVG 2 spec, and it was not restricted, so those elements could reference arbitrary external documents. SVG <use> can load and render external SVG content by reference, and if the referenced document is same-origin and contains scripts, it could execute in the context of the sanitized document. <feImage> can load external images, which can be used for tracking.

Applications are impacted only when the allowed tags are overridden to include one of these SVG reference elements, for example <use> or <feImage>. The default allowed tags do not include these SVG elements, so applications using the default configuration are not affected.

Workarounds

Remove the SVG reference elements (such as use and feImage) from the overridden allowed tags. Applications using the default allowed tags are not affected.

References

• GHSA-9wjq-cp2p-hrgf: SVG href attribute bypasses local-reference restriction in Loofah
• CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Credit

Found by maintainer Mike Dalessio during a security audit.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer. This is due to an incomplete fix of CVE-2022-32209.

• Versions affected: ALL
• Not affected: NONE
• Fixed versions: 1.4.4

Impact

A possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer may allow an attacker to inject content if the application developer has overridden the sanitizer's allowed tags to allow both "select" and "style" elements.

Code is only impacted if allowed tags are being overridden using either of the following two mechanisms:

1. Using the Rails configuration config.action_view.sanitized_allow_tags=:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["select", "style"]

(see https://guides.rubyonrails.org/configuring.html#configuring-action-view)

2. Using the class method Rails::Html::SafeListSanitizer.allowed_tags=:

# class-level option
Rails::Html::SafeListSanitizer.allowed_tags = ["select", "style"]

All users overriding the allowed tags by either of the above mechanisms to include both "select" and "style" should either upgrade or use one of the workarounds immediately.

NOTE: Code is not impacted if allowed tags are overridden using either of the following mechanisms:

• the :tags option to the Action View helper method sanitize.
• the :tags option to the instance method SafeListSanitizer#sanitize.

Workarounds

Remove either "select" or "style" from the overridden allowed tags.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-32209
• https://hackerone.com/reports/1654310

Credit

This vulnerability was responsibly reported by Dominic Breuker.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer.

• Versions affected: ALL
• Not affected: NONE
• Fixed versions: 1.4.4

Impact

A possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer may allow an attacker to inject content if the application developer has overridden the sanitizer's allowed tags in either of the following ways:

• allow both "math" and "style" elements,
• or allow both "svg" and "style" elements

Code is only impacted if allowed tags are being overridden. Applications may be doing this in four different ways:

1. using application configuration:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["math", "style"]
# or
config.action_view.sanitized_allowed_tags = ["svg", "style"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

2. using a :tags option to the Action View helper sanitize:

<%= sanitize @comment.body, tags: ["math", "style"] %>
<%# or %>
<%= sanitize @comment.body, tags: ["svg", "style"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

3. using Rails::Html::SafeListSanitizer class method allowed_tags=:

# class-level option
Rails::Html::SafeListSanitizer.allowed_tags = ["math", "style"]
# or
Rails::Html::SafeListSanitizer.allowed_tags = ["svg", "style"]

4. using a :tags options to the Rails::Html::SafeListSanitizer instance method sanitize:

# instance-level option
Rails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["math", "style"])
# or
Rails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["svg", "style"])

All users overriding the allowed tags by any of the above mechanisms to include (("math" or "svg") and "style") should either upgrade or use one of the workarounds immediately.

Workarounds

Remove "style" from the overridden allowed tags, or remove "math" and "svg" from the overridden allowed tags.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• https://hackerone.com/reports/1656627

Credit

This vulnerability was responsibly reported by Dominic Breuker.

Summary

rails-html-sanitizer >= 1.0.3, < 1.4.4 is vulnerable to cross-site scripting via data URIs when used in combination with Loofah >= 2.1.0.

Mitigation

Upgrade to rails-html-sanitizer >= 1.4.4.

Severity

The maintainers have evaluated this as Medium Severity 6.1.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• SVG MIME Type (image/svg+xml) is misleading to developers · Issue #266 · w3c/svgwg
• https://github.com/rails/rails-html-sanitizer/issues/135
• https://hackerone.com/reports/1694173

Credit

This vulnerability was independently reported by Maciej Piechota (@haqpl) and Mrinmoy Das (@goromlagche).

Summary

Certain configurations of rails-html-sanitizer < 1.4.4 use an inefficient regular expression that is susceptible to excessive backtracking when attempting to sanitize certain SVG attributes. This may lead to a denial of service through CPU resource consumption.

Mitigation

Upgrade to rails-html-sanitizer >= 1.4.4.

Severity

The maintainers have evaluated this as High Severity 7.5 (CVSS3.1).

References

• CWE - CWE-1333: Inefficient Regular Expression Complexity (4.9)
• https://hackerone.com/reports/1684163

Credit

This vulnerability was responsibly reported by @ooooooo-q (https://github.com/ooooooo-q).

Versions of Rails::Html::Sanitizer prior to version 1.4.3 are vulnerable to XSS with certain configurations of Rails::Html::Sanitizer which allows an attacker to inject content when the application developer has overridden the sanitizer's allowed tags to allow both select and style elements. Code is only impacted if allowed tags are being overridden.

This may be done via application configuration: ruby# In config/application.rbconfig.action_view.sanitized_allowed_tags = ["select", "style"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

Or it may be done with a :tags option to the Action View helper sanitize: <%= sanitize @comment.body, tags: ["select", "style"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

It may also be done with Rails::Html::SafeListSanitizer directly: ruby# class-level optionRails::Html::SafeListSanitizer.allowed_tags = ["select", "style"] or with ruby# instance-level optionRails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["select", "style"])

All users overriding the allowed tags by any of the above mechanisms to include both "select" and "style" are recommended to upgrade immediately. A workaround for this issue can be applied by removing either select or style from the overridden allowed tags.

Summary

There is a possible cross-site scripting vulnerability in rails-html-sanitizer when the sanitizer is configured to allow an SVG reference element such as <use>. See related GHSA-9wjq-cp2p-hrgf in Loofah, whose SVG local-reference logic rails-html-sanitizer mirrors.

• Versions affected: >= 1.0.3, < 1.7.1
• Not affected: < 1.0.3
• Fixed versions: 1.7.1

Impact

Rails::HTML::PermitScrubber restricts SVG reference elements in the SVG_ALLOW_LOCAL_HREF collection to local, same-document references, but that restriction covered only the xlink:href attribute. Browsers also accept a plain href attribute per the SVG 2 spec, and it was not restricted, so those elements could reference arbitrary external documents. SVG <use> can load and render external SVG content by reference, and if the referenced document is same-origin and contains scripts, it could execute in the context of the sanitized document. <feImage> can load external images, which can be used for tracking.

Applications are impacted only when the allowed tags are overridden to include one of these SVG reference elements, for example <use> or <feImage>. The default allowed tags do not include these SVG elements, so applications using the default configuration are not affected.

Workarounds

Remove the SVG reference elements (such as use and feImage) from the overridden allowed tags. Applications using the default allowed tags are not affected.

References

• GHSA-9wjq-cp2p-hrgf: SVG href attribute bypasses local-reference restriction in Loofah
• CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Credit

Found by maintainer Mike Dalessio during a security audit.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer. This is due to an incomplete fix of CVE-2022-32209.

• Versions affected: ALL
• Not affected: NONE
• Fixed versions: 1.4.4

Impact

A possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer may allow an attacker to inject content if the application developer has overridden the sanitizer's allowed tags to allow both "select" and "style" elements.

Code is only impacted if allowed tags are being overridden using either of the following two mechanisms:

1. Using the Rails configuration config.action_view.sanitized_allow_tags=:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["select", "style"]

(see https://guides.rubyonrails.org/configuring.html#configuring-action-view)

2. Using the class method Rails::Html::SafeListSanitizer.allowed_tags=:

# class-level option
Rails::Html::SafeListSanitizer.allowed_tags = ["select", "style"]

All users overriding the allowed tags by either of the above mechanisms to include both "select" and "style" should either upgrade or use one of the workarounds immediately.

NOTE: Code is not impacted if allowed tags are overridden using either of the following mechanisms:

• the :tags option to the Action View helper method sanitize.
• the :tags option to the instance method SafeListSanitizer#sanitize.

Workarounds

Remove either "select" or "style" from the overridden allowed tags.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-32209
• https://hackerone.com/reports/1654310

Credit

This vulnerability was responsibly reported by Dominic Breuker.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer.

• Versions affected: ALL
• Not affected: NONE
• Fixed versions: 1.4.4

Impact

A possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer may allow an attacker to inject content if the application developer has overridden the sanitizer's allowed tags in either of the following ways:

• allow both "math" and "style" elements,
• or allow both "svg" and "style" elements

Code is only impacted if allowed tags are being overridden. Applications may be doing this in four different ways:

1. using application configuration:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["math", "style"]
# or
config.action_view.sanitized_allowed_tags = ["svg", "style"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

2. using a :tags option to the Action View helper sanitize:

<%= sanitize @comment.body, tags: ["math", "style"] %>
<%# or %>
<%= sanitize @comment.body, tags: ["svg", "style"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

3. using Rails::Html::SafeListSanitizer class method allowed_tags=:

# class-level option
Rails::Html::SafeListSanitizer.allowed_tags = ["math", "style"]
# or
Rails::Html::SafeListSanitizer.allowed_tags = ["svg", "style"]

4. using a :tags options to the Rails::Html::SafeListSanitizer instance method sanitize:

# instance-level option
Rails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["math", "style"])
# or
Rails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["svg", "style"])

All users overriding the allowed tags by any of the above mechanisms to include (("math" or "svg") and "style") should either upgrade or use one of the workarounds immediately.

Workarounds

Remove "style" from the overridden allowed tags, or remove "math" and "svg" from the overridden allowed tags.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• https://hackerone.com/reports/1656627

Credit

This vulnerability was responsibly reported by Dominic Breuker.

Summary

rails-html-sanitizer >= 1.0.3, < 1.4.4 is vulnerable to cross-site scripting via data URIs when used in combination with Loofah >= 2.1.0.

Mitigation

Upgrade to rails-html-sanitizer >= 1.4.4.

Severity

The maintainers have evaluated this as Medium Severity 6.1.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• SVG MIME Type (image/svg+xml) is misleading to developers · Issue #266 · w3c/svgwg
• https://github.com/rails/rails-html-sanitizer/issues/135
• https://hackerone.com/reports/1694173

Credit

This vulnerability was independently reported by Maciej Piechota (@haqpl) and Mrinmoy Das (@goromlagche).

Summary

Certain configurations of rails-html-sanitizer < 1.4.4 use an inefficient regular expression that is susceptible to excessive backtracking when attempting to sanitize certain SVG attributes. This may lead to a denial of service through CPU resource consumption.

Mitigation

Upgrade to rails-html-sanitizer >= 1.4.4.

Severity

The maintainers have evaluated this as High Severity 7.5 (CVSS3.1).

References

• CWE - CWE-1333: Inefficient Regular Expression Complexity (4.9)
• https://hackerone.com/reports/1684163

Credit

This vulnerability was responsibly reported by @ooooooo-q (https://github.com/ooooooo-q).

Versions of Rails::Html::Sanitizer prior to version 1.4.3 are vulnerable to XSS with certain configurations of Rails::Html::Sanitizer which allows an attacker to inject content when the application developer has overridden the sanitizer's allowed tags to allow both select and style elements. Code is only impacted if allowed tags are being overridden.

This may be done via application configuration: ruby# In config/application.rbconfig.action_view.sanitized_allowed_tags = ["select", "style"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

Or it may be done with a :tags option to the Action View helper sanitize: <%= sanitize @comment.body, tags: ["select", "style"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

It may also be done with Rails::Html::SafeListSanitizer directly: ruby# class-level optionRails::Html::SafeListSanitizer.allowed_tags = ["select", "style"] or with ruby# instance-level optionRails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["select", "style"])

All users overriding the allowed tags by any of the above mechanisms to include both "select" and "style" are recommended to upgrade immediately. A workaround for this issue can be applied by removing either select or style from the overridden allowed tags.

Summary

There is a possible cross-site scripting vulnerability in rails-html-sanitizer when the sanitizer is configured to allow an SVG reference element such as <use>. See related GHSA-9wjq-cp2p-hrgf in Loofah, whose SVG local-reference logic rails-html-sanitizer mirrors.

• Versions affected: >= 1.0.3, < 1.7.1
• Not affected: < 1.0.3
• Fixed versions: 1.7.1

Impact

Rails::HTML::PermitScrubber restricts SVG reference elements in the SVG_ALLOW_LOCAL_HREF collection to local, same-document references, but that restriction covered only the xlink:href attribute. Browsers also accept a plain href attribute per the SVG 2 spec, and it was not restricted, so those elements could reference arbitrary external documents. SVG <use> can load and render external SVG content by reference, and if the referenced document is same-origin and contains scripts, it could execute in the context of the sanitized document. <feImage> can load external images, which can be used for tracking.

Applications are impacted only when the allowed tags are overridden to include one of these SVG reference elements, for example <use> or <feImage>. The default allowed tags do not include these SVG elements, so applications using the default configuration are not affected.

Workarounds

Remove the SVG reference elements (such as use and feImage) from the overridden allowed tags. Applications using the default allowed tags are not affected.

References

• GHSA-9wjq-cp2p-hrgf: SVG href attribute bypasses local-reference restriction in Loofah
• CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Credit

Found by maintainer Mike Dalessio during a security audit.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer. This is due to an incomplete fix of CVE-2022-32209.

• Versions affected: ALL
• Not affected: NONE
• Fixed versions: 1.4.4

Impact

A possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer may allow an attacker to inject content if the application developer has overridden the sanitizer's allowed tags to allow both "select" and "style" elements.

Code is only impacted if allowed tags are being overridden using either of the following two mechanisms:

1. Using the Rails configuration config.action_view.sanitized_allow_tags=:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["select", "style"]

(see https://guides.rubyonrails.org/configuring.html#configuring-action-view)

2. Using the class method Rails::Html::SafeListSanitizer.allowed_tags=:

# class-level option
Rails::Html::SafeListSanitizer.allowed_tags = ["select", "style"]

All users overriding the allowed tags by either of the above mechanisms to include both "select" and "style" should either upgrade or use one of the workarounds immediately.

NOTE: Code is not impacted if allowed tags are overridden using either of the following mechanisms:

• the :tags option to the Action View helper method sanitize.
• the :tags option to the instance method SafeListSanitizer#sanitize.

Workarounds

Remove either "select" or "style" from the overridden allowed tags.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-32209
• https://hackerone.com/reports/1654310

Credit

This vulnerability was responsibly reported by Dominic Breuker.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer.

• Versions affected: ALL
• Not affected: NONE
• Fixed versions: 1.4.4

Impact

A possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer may allow an attacker to inject content if the application developer has overridden the sanitizer's allowed tags in either of the following ways:

• allow both "math" and "style" elements,
• or allow both "svg" and "style" elements

Code is only impacted if allowed tags are being overridden. Applications may be doing this in four different ways:

1. using application configuration:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["math", "style"]
# or
config.action_view.sanitized_allowed_tags = ["svg", "style"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

2. using a :tags option to the Action View helper sanitize:

<%= sanitize @comment.body, tags: ["math", "style"] %>
<%# or %>
<%= sanitize @comment.body, tags: ["svg", "style"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

3. using Rails::Html::SafeListSanitizer class method allowed_tags=:

# class-level option
Rails::Html::SafeListSanitizer.allowed_tags = ["math", "style"]
# or
Rails::Html::SafeListSanitizer.allowed_tags = ["svg", "style"]

4. using a :tags options to the Rails::Html::SafeListSanitizer instance method sanitize:

# instance-level option
Rails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["math", "style"])
# or
Rails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["svg", "style"])

All users overriding the allowed tags by any of the above mechanisms to include (("math" or "svg") and "style") should either upgrade or use one of the workarounds immediately.

Workarounds

Remove "style" from the overridden allowed tags, or remove "math" and "svg" from the overridden allowed tags.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• https://hackerone.com/reports/1656627

Credit

This vulnerability was responsibly reported by Dominic Breuker.

Summary

rails-html-sanitizer >= 1.0.3, < 1.4.4 is vulnerable to cross-site scripting via data URIs when used in combination with Loofah >= 2.1.0.

Mitigation

Upgrade to rails-html-sanitizer >= 1.4.4.

Severity

The maintainers have evaluated this as Medium Severity 6.1.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• SVG MIME Type (image/svg+xml) is misleading to developers · Issue #266 · w3c/svgwg
• https://github.com/rails/rails-html-sanitizer/issues/135
• https://hackerone.com/reports/1694173

Credit

This vulnerability was independently reported by Maciej Piechota (@haqpl) and Mrinmoy Das (@goromlagche).

Summary

Certain configurations of rails-html-sanitizer < 1.4.4 use an inefficient regular expression that is susceptible to excessive backtracking when attempting to sanitize certain SVG attributes. This may lead to a denial of service through CPU resource consumption.

Mitigation

Upgrade to rails-html-sanitizer >= 1.4.4.

Severity

The maintainers have evaluated this as High Severity 7.5 (CVSS3.1).

References

• CWE - CWE-1333: Inefficient Regular Expression Complexity (4.9)
• https://hackerone.com/reports/1684163

Credit

This vulnerability was responsibly reported by @ooooooo-q (https://github.com/ooooooo-q).

Versions of Rails::Html::Sanitizer prior to version 1.4.3 are vulnerable to XSS with certain configurations of Rails::Html::Sanitizer which allows an attacker to inject content when the application developer has overridden the sanitizer's allowed tags to allow both select and style elements. Code is only impacted if allowed tags are being overridden.

This may be done via application configuration: ruby# In config/application.rbconfig.action_view.sanitized_allowed_tags = ["select", "style"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

Or it may be done with a :tags option to the Action View helper sanitize: <%= sanitize @comment.body, tags: ["select", "style"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

It may also be done with Rails::Html::SafeListSanitizer directly: ruby# class-level optionRails::Html::SafeListSanitizer.allowed_tags = ["select", "style"] or with ruby# instance-level optionRails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["select", "style"])

All users overriding the allowed tags by any of the above mechanisms to include both "select" and "style" are recommended to upgrade immediately. A workaround for this issue can be applied by removing either select or style from the overridden allowed tags.

Summary

There is a possible cross-site scripting vulnerability in rails-html-sanitizer when the sanitizer is configured to allow an SVG reference element such as <use>. See related GHSA-9wjq-cp2p-hrgf in Loofah, whose SVG local-reference logic rails-html-sanitizer mirrors.

• Versions affected: >= 1.0.3, < 1.7.1
• Not affected: < 1.0.3
• Fixed versions: 1.7.1

Impact

Rails::HTML::PermitScrubber restricts SVG reference elements in the SVG_ALLOW_LOCAL_HREF collection to local, same-document references, but that restriction covered only the xlink:href attribute. Browsers also accept a plain href attribute per the SVG 2 spec, and it was not restricted, so those elements could reference arbitrary external documents. SVG <use> can load and render external SVG content by reference, and if the referenced document is same-origin and contains scripts, it could execute in the context of the sanitized document. <feImage> can load external images, which can be used for tracking.

Applications are impacted only when the allowed tags are overridden to include one of these SVG reference elements, for example <use> or <feImage>. The default allowed tags do not include these SVG elements, so applications using the default configuration are not affected.

Workarounds

Remove the SVG reference elements (such as use and feImage) from the overridden allowed tags. Applications using the default allowed tags are not affected.

References

• GHSA-9wjq-cp2p-hrgf: SVG href attribute bypasses local-reference restriction in Loofah
• CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Credit

Found by maintainer Mike Dalessio during a security audit.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer. This is due to an incomplete fix of CVE-2022-32209.

• Versions affected: ALL
• Not affected: NONE
• Fixed versions: 1.4.4

Impact

A possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer may allow an attacker to inject content if the application developer has overridden the sanitizer's allowed tags to allow both "select" and "style" elements.

Code is only impacted if allowed tags are being overridden using either of the following two mechanisms:

1. Using the Rails configuration config.action_view.sanitized_allow_tags=:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["select", "style"]

(see https://guides.rubyonrails.org/configuring.html#configuring-action-view)

2. Using the class method Rails::Html::SafeListSanitizer.allowed_tags=:

# class-level option
Rails::Html::SafeListSanitizer.allowed_tags = ["select", "style"]

All users overriding the allowed tags by either of the above mechanisms to include both "select" and "style" should either upgrade or use one of the workarounds immediately.

NOTE: Code is not impacted if allowed tags are overridden using either of the following mechanisms:

• the :tags option to the Action View helper method sanitize.
• the :tags option to the instance method SafeListSanitizer#sanitize.

Workarounds

Remove either "select" or "style" from the overridden allowed tags.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-32209
• https://hackerone.com/reports/1654310

Credit

This vulnerability was responsibly reported by Dominic Breuker.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer.

• Versions affected: ALL
• Not affected: NONE
• Fixed versions: 1.4.4

Impact

A possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer may allow an attacker to inject content if the application developer has overridden the sanitizer's allowed tags in either of the following ways:

• allow both "math" and "style" elements,
• or allow both "svg" and "style" elements

Code is only impacted if allowed tags are being overridden. Applications may be doing this in four different ways:

1. using application configuration:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["math", "style"]
# or
config.action_view.sanitized_allowed_tags = ["svg", "style"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

2. using a :tags option to the Action View helper sanitize:

<%= sanitize @comment.body, tags: ["math", "style"] %>
<%# or %>
<%= sanitize @comment.body, tags: ["svg", "style"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

3. using Rails::Html::SafeListSanitizer class method allowed_tags=:

# class-level option
Rails::Html::SafeListSanitizer.allowed_tags = ["math", "style"]
# or
Rails::Html::SafeListSanitizer.allowed_tags = ["svg", "style"]

4. using a :tags options to the Rails::Html::SafeListSanitizer instance method sanitize:

# instance-level option
Rails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["math", "style"])
# or
Rails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["svg", "style"])

All users overriding the allowed tags by any of the above mechanisms to include (("math" or "svg") and "style") should either upgrade or use one of the workarounds immediately.

Workarounds

Remove "style" from the overridden allowed tags, or remove "math" and "svg" from the overridden allowed tags.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• https://hackerone.com/reports/1656627

Credit

This vulnerability was responsibly reported by Dominic Breuker.

Summary

rails-html-sanitizer >= 1.0.3, < 1.4.4 is vulnerable to cross-site scripting via data URIs when used in combination with Loofah >= 2.1.0.

Mitigation

Upgrade to rails-html-sanitizer >= 1.4.4.

Severity

The maintainers have evaluated this as Medium Severity 6.1.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• SVG MIME Type (image/svg+xml) is misleading to developers · Issue #266 · w3c/svgwg
• https://github.com/rails/rails-html-sanitizer/issues/135
• https://hackerone.com/reports/1694173

Credit

This vulnerability was independently reported by Maciej Piechota (@haqpl) and Mrinmoy Das (@goromlagche).

Summary

Certain configurations of rails-html-sanitizer < 1.4.4 use an inefficient regular expression that is susceptible to excessive backtracking when attempting to sanitize certain SVG attributes. This may lead to a denial of service through CPU resource consumption.

Mitigation

Upgrade to rails-html-sanitizer >= 1.4.4.

Severity

The maintainers have evaluated this as High Severity 7.5 (CVSS3.1).

References

• CWE - CWE-1333: Inefficient Regular Expression Complexity (4.9)
• https://hackerone.com/reports/1684163

Credit

This vulnerability was responsibly reported by @ooooooo-q (https://github.com/ooooooo-q).

Versions of Rails::Html::Sanitizer prior to version 1.4.3 are vulnerable to XSS with certain configurations of Rails::Html::Sanitizer which allows an attacker to inject content when the application developer has overridden the sanitizer's allowed tags to allow both select and style elements. Code is only impacted if allowed tags are being overridden.

This may be done via application configuration: ruby# In config/application.rbconfig.action_view.sanitized_allowed_tags = ["select", "style"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

Or it may be done with a :tags option to the Action View helper sanitize: <%= sanitize @comment.body, tags: ["select", "style"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

It may also be done with Rails::Html::SafeListSanitizer directly: ruby# class-level optionRails::Html::SafeListSanitizer.allowed_tags = ["select", "style"] or with ruby# instance-level optionRails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["select", "style"])

All users overriding the allowed tags by any of the above mechanisms to include both "select" and "style" are recommended to upgrade immediately. A workaround for this issue can be applied by removing either select or style from the overridden allowed tags.

Summary

There is a possible cross-site scripting vulnerability in rails-html-sanitizer when the sanitizer is configured to allow an SVG reference element such as <use>. See related GHSA-9wjq-cp2p-hrgf in Loofah, whose SVG local-reference logic rails-html-sanitizer mirrors.

• Versions affected: >= 1.0.3, < 1.7.1
• Not affected: < 1.0.3
• Fixed versions: 1.7.1

Impact

Rails::HTML::PermitScrubber restricts SVG reference elements in the SVG_ALLOW_LOCAL_HREF collection to local, same-document references, but that restriction covered only the xlink:href attribute. Browsers also accept a plain href attribute per the SVG 2 spec, and it was not restricted, so those elements could reference arbitrary external documents. SVG <use> can load and render external SVG content by reference, and if the referenced document is same-origin and contains scripts, it could execute in the context of the sanitized document. <feImage> can load external images, which can be used for tracking.

Applications are impacted only when the allowed tags are overridden to include one of these SVG reference elements, for example <use> or <feImage>. The default allowed tags do not include these SVG elements, so applications using the default configuration are not affected.

Workarounds

Remove the SVG reference elements (such as use and feImage) from the overridden allowed tags. Applications using the default allowed tags are not affected.

References

• GHSA-9wjq-cp2p-hrgf: SVG href attribute bypasses local-reference restriction in Loofah
• CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Credit

Found by maintainer Mike Dalessio during a security audit.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer. This is due to an incomplete fix of CVE-2022-32209.

• Versions affected: ALL
• Not affected: NONE
• Fixed versions: 1.4.4

Impact

A possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer may allow an attacker to inject content if the application developer has overridden the sanitizer's allowed tags to allow both "select" and "style" elements.

Code is only impacted if allowed tags are being overridden using either of the following two mechanisms:

1. Using the Rails configuration config.action_view.sanitized_allow_tags=:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["select", "style"]

(see https://guides.rubyonrails.org/configuring.html#configuring-action-view)

2. Using the class method Rails::Html::SafeListSanitizer.allowed_tags=:

# class-level option
Rails::Html::SafeListSanitizer.allowed_tags = ["select", "style"]

All users overriding the allowed tags by either of the above mechanisms to include both "select" and "style" should either upgrade or use one of the workarounds immediately.

NOTE: Code is not impacted if allowed tags are overridden using either of the following mechanisms:

• the :tags option to the Action View helper method sanitize.
• the :tags option to the instance method SafeListSanitizer#sanitize.

Workarounds

Remove either "select" or "style" from the overridden allowed tags.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-32209
• https://hackerone.com/reports/1654310

Credit

This vulnerability was responsibly reported by Dominic Breuker.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer.

• Versions affected: ALL
• Not affected: NONE
• Fixed versions: 1.4.4

Impact

A possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer may allow an attacker to inject content if the application developer has overridden the sanitizer's allowed tags in either of the following ways:

• allow both "math" and "style" elements,
• or allow both "svg" and "style" elements

Code is only impacted if allowed tags are being overridden. Applications may be doing this in four different ways:

1. using application configuration:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["math", "style"]
# or
config.action_view.sanitized_allowed_tags = ["svg", "style"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

2. using a :tags option to the Action View helper sanitize:

<%= sanitize @comment.body, tags: ["math", "style"] %>
<%# or %>
<%= sanitize @comment.body, tags: ["svg", "style"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

3. using Rails::Html::SafeListSanitizer class method allowed_tags=:

# class-level option
Rails::Html::SafeListSanitizer.allowed_tags = ["math", "style"]
# or
Rails::Html::SafeListSanitizer.allowed_tags = ["svg", "style"]

4. using a :tags options to the Rails::Html::SafeListSanitizer instance method sanitize:

# instance-level option
Rails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["math", "style"])
# or
Rails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["svg", "style"])

All users overriding the allowed tags by any of the above mechanisms to include (("math" or "svg") and "style") should either upgrade or use one of the workarounds immediately.

Workarounds

Remove "style" from the overridden allowed tags, or remove "math" and "svg" from the overridden allowed tags.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• https://hackerone.com/reports/1656627

Credit

This vulnerability was responsibly reported by Dominic Breuker.

Summary

rails-html-sanitizer >= 1.0.3, < 1.4.4 is vulnerable to cross-site scripting via data URIs when used in combination with Loofah >= 2.1.0.

Mitigation

Upgrade to rails-html-sanitizer >= 1.4.4.

Severity

The maintainers have evaluated this as Medium Severity 6.1.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• SVG MIME Type (image/svg+xml) is misleading to developers · Issue #266 · w3c/svgwg
• https://github.com/rails/rails-html-sanitizer/issues/135
• https://hackerone.com/reports/1694173

Credit

This vulnerability was independently reported by Maciej Piechota (@haqpl) and Mrinmoy Das (@goromlagche).

Summary

Certain configurations of rails-html-sanitizer < 1.4.4 use an inefficient regular expression that is susceptible to excessive backtracking when attempting to sanitize certain SVG attributes. This may lead to a denial of service through CPU resource consumption.

Mitigation

Upgrade to rails-html-sanitizer >= 1.4.4.

Severity

The maintainers have evaluated this as High Severity 7.5 (CVSS3.1).

References

• CWE - CWE-1333: Inefficient Regular Expression Complexity (4.9)
• https://hackerone.com/reports/1684163

Credit

This vulnerability was responsibly reported by @ooooooo-q (https://github.com/ooooooo-q).

Versions of Rails::Html::Sanitizer prior to version 1.4.3 are vulnerable to XSS with certain configurations of Rails::Html::Sanitizer which allows an attacker to inject content when the application developer has overridden the sanitizer's allowed tags to allow both select and style elements. Code is only impacted if allowed tags are being overridden.

This may be done via application configuration: ruby# In config/application.rbconfig.action_view.sanitized_allowed_tags = ["select", "style"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

Or it may be done with a :tags option to the Action View helper sanitize: <%= sanitize @comment.body, tags: ["select", "style"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

It may also be done with Rails::Html::SafeListSanitizer directly: ruby# class-level optionRails::Html::SafeListSanitizer.allowed_tags = ["select", "style"] or with ruby# instance-level optionRails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["select", "style"])

All users overriding the allowed tags by any of the above mechanisms to include both "select" and "style" are recommended to upgrade immediately. A workaround for this issue can be applied by removing either select or style from the overridden allowed tags.

There is a possible XSS vulnerability in all rails-html-sanitizer gem versions below 1.0.4 for Ruby. The gem allows non-whitelisted attributes to be present in sanitized output when input with specially-crafted HTML fragments, and these attributes can lead to an XSS attack on target applications. This issue is similar to CVE-2018-8048 in Loofah. All users running an affected release should either upgrade or use one of the workarounds immediately.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer. This is due to an incomplete fix of CVE-2022-32209.

• Versions affected: ALL
• Not affected: NONE
• Fixed versions: 1.4.4

Impact

A possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer may allow an attacker to inject content if the application developer has overridden the sanitizer's allowed tags to allow both "select" and "style" elements.

Code is only impacted if allowed tags are being overridden using either of the following two mechanisms:

1. Using the Rails configuration config.action_view.sanitized_allow_tags=:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["select", "style"]

(see https://guides.rubyonrails.org/configuring.html#configuring-action-view)

2. Using the class method Rails::Html::SafeListSanitizer.allowed_tags=:

# class-level option
Rails::Html::SafeListSanitizer.allowed_tags = ["select", "style"]

All users overriding the allowed tags by either of the above mechanisms to include both "select" and "style" should either upgrade or use one of the workarounds immediately.

NOTE: Code is not impacted if allowed tags are overridden using either of the following mechanisms:

• the :tags option to the Action View helper method sanitize.
• the :tags option to the instance method SafeListSanitizer#sanitize.

Workarounds

Remove either "select" or "style" from the overridden allowed tags.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-32209
• https://hackerone.com/reports/1654310

Credit

This vulnerability was responsibly reported by Dominic Breuker.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer.

• Versions affected: ALL
• Not affected: NONE
• Fixed versions: 1.4.4

Impact

A possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer may allow an attacker to inject content if the application developer has overridden the sanitizer's allowed tags in either of the following ways:

• allow both "math" and "style" elements,
• or allow both "svg" and "style" elements

Code is only impacted if allowed tags are being overridden. Applications may be doing this in four different ways:

1. using application configuration:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["math", "style"]
# or
config.action_view.sanitized_allowed_tags = ["svg", "style"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

2. using a :tags option to the Action View helper sanitize:

<%= sanitize @comment.body, tags: ["math", "style"] %>
<%# or %>
<%= sanitize @comment.body, tags: ["svg", "style"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

3. using Rails::Html::SafeListSanitizer class method allowed_tags=:

# class-level option
Rails::Html::SafeListSanitizer.allowed_tags = ["math", "style"]
# or
Rails::Html::SafeListSanitizer.allowed_tags = ["svg", "style"]

4. using a :tags options to the Rails::Html::SafeListSanitizer instance method sanitize:

# instance-level option
Rails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["math", "style"])
# or
Rails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["svg", "style"])

All users overriding the allowed tags by any of the above mechanisms to include (("math" or "svg") and "style") should either upgrade or use one of the workarounds immediately.

Workarounds

Remove "style" from the overridden allowed tags, or remove "math" and "svg" from the overridden allowed tags.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• https://hackerone.com/reports/1656627

Credit

This vulnerability was responsibly reported by Dominic Breuker.

Summary

Certain configurations of rails-html-sanitizer < 1.4.4 use an inefficient regular expression that is susceptible to excessive backtracking when attempting to sanitize certain SVG attributes. This may lead to a denial of service through CPU resource consumption.

Mitigation

Upgrade to rails-html-sanitizer >= 1.4.4.

Severity

The maintainers have evaluated this as High Severity 7.5 (CVSS3.1).

References

• CWE - CWE-1333: Inefficient Regular Expression Complexity (4.9)
• https://hackerone.com/reports/1684163

Credit

This vulnerability was responsibly reported by @ooooooo-q (https://github.com/ooooooo-q).

Versions of Rails::Html::Sanitizer prior to version 1.4.3 are vulnerable to XSS with certain configurations of Rails::Html::Sanitizer which allows an attacker to inject content when the application developer has overridden the sanitizer's allowed tags to allow both select and style elements. Code is only impacted if allowed tags are being overridden.

This may be done via application configuration: ruby# In config/application.rbconfig.action_view.sanitized_allowed_tags = ["select", "style"]

see https://guides.rubyonrails.org/configuring.html#configuring-action-view

Or it may be done with a :tags option to the Action View helper sanitize: <%= sanitize @comment.body, tags: ["select", "style"] %>

see https://api.rubyonrails.org/classes/ActionView/Helpers/SanitizeHelper.html#method-i-sanitize

It may also be done with Rails::Html::SafeListSanitizer directly: ruby# class-level optionRails::Html::SafeListSanitizer.allowed_tags = ["select", "style"] or with ruby# instance-level optionRails::Html::SafeListSanitizer.new.sanitize(@article.body, tags: ["select", "style"])

All users overriding the allowed tags by any of the above mechanisms to include both "select" and "style" are recommended to upgrade immediately. A workaround for this issue can be applied by removing either select or style from the overridden allowed tags.

There is a possible XSS vulnerability in all rails-html-sanitizer gem versions below 1.0.4 for Ruby. The gem allows non-whitelisted attributes to be present in sanitized output when input with specially-crafted HTML fragments, and these attributes can lead to an XSS attack on target applications. This issue is similar to CVE-2018-8048 in Loofah. All users running an affected release should either upgrade or use one of the workarounds immediately.

Cross-site scripting (XSS) vulnerability in the rails-html-sanitizer gem before 1.0.3 for Ruby on Rails 4.2.x and 5.x allows remote attackers to inject arbitrary web script or HTML via crafted tag attributes.

Cross-site scripting (XSS) vulnerability in the rails-html-sanitizer gem 1.0.2 for Ruby on Rails 4.2.x and 5.x allows remote attackers to inject arbitrary web script or HTML via an HTML entity that is mishandled by the Rails::Html::FullSanitizer class.

Cross-site scripting (XSS) vulnerability in lib/rails/html/scrubbers.rb in the rails-html-sanitizer gem before 1.0.3 for Ruby on Rails 4.2.x and 5.x allows remote attackers to inject arbitrary web script or HTML via a crafted CDATA node.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer. This is due to an incomplete fix of CVE-2022-32209.

• Versions affected: ALL
• Not affected: NONE
• Fixed versions: 1.4.4

Impact

A possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer may allow an attacker to inject content if the application developer has overridden the sanitizer's allowed tags to allow both "select" and "style" elements.

Code is only impacted if allowed tags are being overridden using either of the following two mechanisms:

1. Using the Rails configuration config.action_view.sanitized_allow_tags=:

# In config/application.rb
config.action_view.sanitized_allowed_tags = ["select", "style"]

(see https://guides.rubyonrails.org/configuring.html#configuring-action-view)

2. Using the class method Rails::Html::SafeListSanitizer.allowed_tags=:

# class-level option
Rails::Html::SafeListSanitizer.allowed_tags = ["select", "style"]

All users overriding the allowed tags by either of the above mechanisms to include both "select" and "style" should either upgrade or use one of the workarounds immediately.

NOTE: Code is not impacted if allowed tags are overridden using either of the following mechanisms:

• the :tags option to the Action View helper method sanitize.
• the :tags option to the instance method SafeListSanitizer#sanitize.

Workarounds

Remove either "select" or "style" from the overridden allowed tags.

References

• CWE - CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (4.9)
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-32209
• https://hackerone.com/reports/1654310

Credit

This vulnerability was responsibly reported by Dominic Breuker.

Summary

There is a possible XSS vulnerability with certain configurations of Rails::Html::Sanitizer.

• Versions affected: ALL
• Not affected: NONE
• Fixed versions: 1.4.4