api-platform/core

Summary

The API Platform serializer's AbstractItemNormalizer does not validate the resource type returned when resolving relation IRIs, allowing type confusion where a resource of an unintended type can be silently assigned to a relation property.

Impact

An attacker who can submit write requests (POST/PUT/PATCH) to an API Platform endpoint with writable relations can supply a relation IRI pointing to a resource of a different type than the relation's declared class. Because getResourceFromIri() does not pass an $operation to IriConverter::getResourceFromIri(), the is_a type guard at IriConverter.php:86 is skipped. For untyped relation properties (legacy @var-only style), the wrong-typed object is silently assigned, corrupting invariants and potentially feeding downstream logic that assumes the declared type (CWE-843). For typed properties (modern PHP 8.x), the substitution is blocked by Symfony's PropertyAccessor with an InvalidTypeException.

Affected versions

• api-platform/core < 4.1.30
• api-platform/core >= 4.2.0, < 4.2.26
• api-platform/core >= 4.3.0, < 4.3.12

Older major series (2.x, 3.x) ship the same vulnerable code path and are end-of-life; no fix is planned.

Patched versions

• 4.1.30
• 4.2.26
• 4.3.12

Fix

An is_a guard is added inside AbstractItemNormalizer::getResourceFromIri() (and the equivalent inline call sites on 4.1) so that a mismatched IRI throws InvalidArgumentException, mirroring the operation-aware check the IriConverter already performs when an operation is supplied. This forces a 400 Bad Request response for cross-type IRIs instead of a silent assignment.

Workarounds

Declare a PHP type on every writable relation property (e.g. public ?Foo $relation = null; instead of @var Foo $relation). Symfony's PropertyAccessor will then reject a mismatched object with InvalidTypeException. This does not cover collections of mixed-type interfaces; upgrading to a patched version is the only complete fix.

Proof of concept

A functional test posts a Bar IRI to a Foo-declared relation on an untyped property. Without the fix the server responds with HTTP 201 and the Bar IRI appears in the response payload. With the fix the server responds with HTTP 400 (Invalid IRI "/bars/1").

Full PoC: tests/Functional/Security/TypeConfusionRelationIriTest.php in the patched branches.

References

• src/Serializer/AbstractItemNormalizer.php — vulnerable relation IRI load
• src/Symfony/Routing/IriConverter.php — conditional is_a guard (operation-aware path)

Credit

Reported by @alexandre-daubois.

Summary

The API Platform serializer's AbstractItemNormalizer does not validate the resource type returned when resolving relation IRIs, allowing type confusion where a resource of an unintended type can be silently assigned to a relation property.

Impact

An attacker who can submit write requests (POST/PUT/PATCH) to an API Platform endpoint with writable relations can supply a relation IRI pointing to a resource of a different type than the relation's declared class. Because getResourceFromIri() does not pass an $operation to IriConverter::getResourceFromIri(), the is_a type guard at IriConverter.php:86 is skipped. For untyped relation properties (legacy @var-only style), the wrong-typed object is silently assigned, corrupting invariants and potentially feeding downstream logic that assumes the declared type (CWE-843). For typed properties (modern PHP 8.x), the substitution is blocked by Symfony's PropertyAccessor with an InvalidTypeException.

Affected versions

• api-platform/core < 4.1.30
• api-platform/core >= 4.2.0, < 4.2.26
• api-platform/core >= 4.3.0, < 4.3.12

Older major series (2.x, 3.x) ship the same vulnerable code path and are end-of-life; no fix is planned.

Patched versions

• 4.1.30
• 4.2.26
• 4.3.12

Fix

An is_a guard is added inside AbstractItemNormalizer::getResourceFromIri() (and the equivalent inline call sites on 4.1) so that a mismatched IRI throws InvalidArgumentException, mirroring the operation-aware check the IriConverter already performs when an operation is supplied. This forces a 400 Bad Request response for cross-type IRIs instead of a silent assignment.

Workarounds

Declare a PHP type on every writable relation property (e.g. public ?Foo $relation = null; instead of @var Foo $relation). Symfony's PropertyAccessor will then reject a mismatched object with InvalidTypeException. This does not cover collections of mixed-type interfaces; upgrading to a patched version is the only complete fix.

Proof of concept

A functional test posts a Bar IRI to a Foo-declared relation on an untyped property. Without the fix the server responds with HTTP 201 and the Bar IRI appears in the response payload. With the fix the server responds with HTTP 400 (Invalid IRI "/bars/1").

Full PoC: tests/Functional/Security/TypeConfusionRelationIriTest.php in the patched branches.

References

• src/Serializer/AbstractItemNormalizer.php — vulnerable relation IRI load
• src/Symfony/Routing/IriConverter.php — conditional is_a guard (operation-aware path)

Credit

Reported by @alexandre-daubois.

Summary

The API Platform serializer's AbstractItemNormalizer does not validate the resource type returned when resolving relation IRIs, allowing type confusion where a resource of an unintended type can be silently assigned to a relation property.

Impact

An attacker who can submit write requests (POST/PUT/PATCH) to an API Platform endpoint with writable relations can supply a relation IRI pointing to a resource of a different type than the relation's declared class. Because getResourceFromIri() does not pass an $operation to IriConverter::getResourceFromIri(), the is_a type guard at IriConverter.php:86 is skipped. For untyped relation properties (legacy @var-only style), the wrong-typed object is silently assigned, corrupting invariants and potentially feeding downstream logic that assumes the declared type (CWE-843). For typed properties (modern PHP 8.x), the substitution is blocked by Symfony's PropertyAccessor with an InvalidTypeException.

Affected versions

• api-platform/core < 4.1.30
• api-platform/core >= 4.2.0, < 4.2.26
• api-platform/core >= 4.3.0, < 4.3.12

Older major series (2.x, 3.x) ship the same vulnerable code path and are end-of-life; no fix is planned.

Patched versions

• 4.1.30
• 4.2.26
• 4.3.12

Fix

An is_a guard is added inside AbstractItemNormalizer::getResourceFromIri() (and the equivalent inline call sites on 4.1) so that a mismatched IRI throws InvalidArgumentException, mirroring the operation-aware check the IriConverter already performs when an operation is supplied. This forces a 400 Bad Request response for cross-type IRIs instead of a silent assignment.

Workarounds

Declare a PHP type on every writable relation property (e.g. public ?Foo $relation = null; instead of @var Foo $relation). Symfony's PropertyAccessor will then reject a mismatched object with InvalidTypeException. This does not cover collections of mixed-type interfaces; upgrading to a patched version is the only complete fix.

Proof of concept

A functional test posts a Bar IRI to a Foo-declared relation on an untyped property. Without the fix the server responds with HTTP 201 and the Bar IRI appears in the response payload. With the fix the server responds with HTTP 400 (Invalid IRI "/bars/1").

Full PoC: tests/Functional/Security/TypeConfusionRelationIriTest.php in the patched branches.

References

• src/Serializer/AbstractItemNormalizer.php — vulnerable relation IRI load
• src/Symfony/Routing/IriConverter.php — conditional is_a guard (operation-aware path)

Credit

Reported by @alexandre-daubois.

Summary

The API Platform serializer's AbstractItemNormalizer does not validate the resource type returned when resolving relation IRIs, allowing type confusion where a resource of an unintended type can be silently assigned to a relation property.

Impact

An attacker who can submit write requests (POST/PUT/PATCH) to an API Platform endpoint with writable relations can supply a relation IRI pointing to a resource of a different type than the relation's declared class. Because getResourceFromIri() does not pass an $operation to IriConverter::getResourceFromIri(), the is_a type guard at IriConverter.php:86 is skipped. For untyped relation properties (legacy @var-only style), the wrong-typed object is silently assigned, corrupting invariants and potentially feeding downstream logic that assumes the declared type (CWE-843). For typed properties (modern PHP 8.x), the substitution is blocked by Symfony's PropertyAccessor with an InvalidTypeException.

Affected versions

• api-platform/core < 4.1.30
• api-platform/core >= 4.2.0, < 4.2.26
• api-platform/core >= 4.3.0, < 4.3.12

Older major series (2.x, 3.x) ship the same vulnerable code path and are end-of-life; no fix is planned.

Patched versions

• 4.1.30
• 4.2.26
• 4.3.12

Fix

An is_a guard is added inside AbstractItemNormalizer::getResourceFromIri() (and the equivalent inline call sites on 4.1) so that a mismatched IRI throws InvalidArgumentException, mirroring the operation-aware check the IriConverter already performs when an operation is supplied. This forces a 400 Bad Request response for cross-type IRIs instead of a silent assignment.

Workarounds

Declare a PHP type on every writable relation property (e.g. public ?Foo $relation = null; instead of @var Foo $relation). Symfony's PropertyAccessor will then reject a mismatched object with InvalidTypeException. This does not cover collections of mixed-type interfaces; upgrading to a patched version is the only complete fix.

Proof of concept

A functional test posts a Bar IRI to a Foo-declared relation on an untyped property. Without the fix the server responds with HTTP 201 and the Bar IRI appears in the response payload. With the fix the server responds with HTTP 400 (Invalid IRI "/bars/1").

Full PoC: tests/Functional/Security/TypeConfusionRelationIriTest.php in the patched branches.

References

• src/Serializer/AbstractItemNormalizer.php — vulnerable relation IRI load
• src/Symfony/Routing/IriConverter.php — conditional is_a guard (operation-aware path)

Credit

Reported by @alexandre-daubois.

Summary

The API Platform serializer's AbstractItemNormalizer does not validate the resource type returned when resolving relation IRIs, allowing type confusion where a resource of an unintended type can be silently assigned to a relation property.

Impact

An attacker who can submit write requests (POST/PUT/PATCH) to an API Platform endpoint with writable relations can supply a relation IRI pointing to a resource of a different type than the relation's declared class. Because getResourceFromIri() does not pass an $operation to IriConverter::getResourceFromIri(), the is_a type guard at IriConverter.php:86 is skipped. For untyped relation properties (legacy @var-only style), the wrong-typed object is silently assigned, corrupting invariants and potentially feeding downstream logic that assumes the declared type (CWE-843). For typed properties (modern PHP 8.x), the substitution is blocked by Symfony's PropertyAccessor with an InvalidTypeException.

Affected versions

• api-platform/core < 4.1.30
• api-platform/core >= 4.2.0, < 4.2.26
• api-platform/core >= 4.3.0, < 4.3.12

Older major series (2.x, 3.x) ship the same vulnerable code path and are end-of-life; no fix is planned.

Patched versions

• 4.1.30
• 4.2.26
• 4.3.12

Fix

An is_a guard is added inside AbstractItemNormalizer::getResourceFromIri() (and the equivalent inline call sites on 4.1) so that a mismatched IRI throws InvalidArgumentException, mirroring the operation-aware check the IriConverter already performs when an operation is supplied. This forces a 400 Bad Request response for cross-type IRIs instead of a silent assignment.

Workarounds

Declare a PHP type on every writable relation property (e.g. public ?Foo $relation = null; instead of @var Foo $relation). Symfony's PropertyAccessor will then reject a mismatched object with InvalidTypeException. This does not cover collections of mixed-type interfaces; upgrading to a patched version is the only complete fix.

Proof of concept

A functional test posts a Bar IRI to a Foo-declared relation on an untyped property. Without the fix the server responds with HTTP 201 and the Bar IRI appears in the response payload. With the fix the server responds with HTTP 400 (Invalid IRI "/bars/1").

Full PoC: tests/Functional/Security/TypeConfusionRelationIriTest.php in the patched branches.

References

• src/Serializer/AbstractItemNormalizer.php — vulnerable relation IRI load
• src/Symfony/Routing/IriConverter.php — conditional is_a guard (operation-aware path)

Credit

Reported by @alexandre-daubois.

Summary

The API Platform serializer's AbstractItemNormalizer does not validate the resource type returned when resolving relation IRIs, allowing type confusion where a resource of an unintended type can be silently assigned to a relation property.

Impact

An attacker who can submit write requests (POST/PUT/PATCH) to an API Platform endpoint with writable relations can supply a relation IRI pointing to a resource of a different type than the relation's declared class. Because getResourceFromIri() does not pass an $operation to IriConverter::getResourceFromIri(), the is_a type guard at IriConverter.php:86 is skipped. For untyped relation properties (legacy @var-only style), the wrong-typed object is silently assigned, corrupting invariants and potentially feeding downstream logic that assumes the declared type (CWE-843). For typed properties (modern PHP 8.x), the substitution is blocked by Symfony's PropertyAccessor with an InvalidTypeException.

Affected versions

• api-platform/core < 4.1.30
• api-platform/core >= 4.2.0, < 4.2.26
• api-platform/core >= 4.3.0, < 4.3.12

Older major series (2.x, 3.x) ship the same vulnerable code path and are end-of-life; no fix is planned.

Patched versions

• 4.1.30
• 4.2.26
• 4.3.12

Fix

An is_a guard is added inside AbstractItemNormalizer::getResourceFromIri() (and the equivalent inline call sites on 4.1) so that a mismatched IRI throws InvalidArgumentException, mirroring the operation-aware check the IriConverter already performs when an operation is supplied. This forces a 400 Bad Request response for cross-type IRIs instead of a silent assignment.

Workarounds

Declare a PHP type on every writable relation property (e.g. public ?Foo $relation = null; instead of @var Foo $relation). Symfony's PropertyAccessor will then reject a mismatched object with InvalidTypeException. This does not cover collections of mixed-type interfaces; upgrading to a patched version is the only complete fix.

Proof of concept

A functional test posts a Bar IRI to a Foo-declared relation on an untyped property. Without the fix the server responds with HTTP 201 and the Bar IRI appears in the response payload. With the fix the server responds with HTTP 400 (Invalid IRI "/bars/1").

Full PoC: tests/Functional/Security/TypeConfusionRelationIriTest.php in the patched branches.

References

• src/Serializer/AbstractItemNormalizer.php — vulnerable relation IRI load
• src/Symfony/Routing/IriConverter.php — conditional is_a guard (operation-aware path)

Credit

Reported by @alexandre-daubois.

Summary

The API Platform serializer's AbstractItemNormalizer does not validate the resource type returned when resolving relation IRIs, allowing type confusion where a resource of an unintended type can be silently assigned to a relation property.

Impact

An attacker who can submit write requests (POST/PUT/PATCH) to an API Platform endpoint with writable relations can supply a relation IRI pointing to a resource of a different type than the relation's declared class. Because getResourceFromIri() does not pass an $operation to IriConverter::getResourceFromIri(), the is_a type guard at IriConverter.php:86 is skipped. For untyped relation properties (legacy @var-only style), the wrong-typed object is silently assigned, corrupting invariants and potentially feeding downstream logic that assumes the declared type (CWE-843). For typed properties (modern PHP 8.x), the substitution is blocked by Symfony's PropertyAccessor with an InvalidTypeException.

Affected versions

• api-platform/core < 4.1.30
• api-platform/core >= 4.2.0, < 4.2.26
• api-platform/core >= 4.3.0, < 4.3.12

Older major series (2.x, 3.x) ship the same vulnerable code path and are end-of-life; no fix is planned.

Patched versions

• 4.1.30
• 4.2.26
• 4.3.12

Fix

An is_a guard is added inside AbstractItemNormalizer::getResourceFromIri() (and the equivalent inline call sites on 4.1) so that a mismatched IRI throws InvalidArgumentException, mirroring the operation-aware check the IriConverter already performs when an operation is supplied. This forces a 400 Bad Request response for cross-type IRIs instead of a silent assignment.

Workarounds

Declare a PHP type on every writable relation property (e.g. public ?Foo $relation = null; instead of @var Foo $relation). Symfony's PropertyAccessor will then reject a mismatched object with InvalidTypeException. This does not cover collections of mixed-type interfaces; upgrading to a patched version is the only complete fix.

Proof of concept

A functional test posts a Bar IRI to a Foo-declared relation on an untyped property. Without the fix the server responds with HTTP 201 and the Bar IRI appears in the response payload. With the fix the server responds with HTTP 400 (Invalid IRI "/bars/1").

Full PoC: tests/Functional/Security/TypeConfusionRelationIriTest.php in the patched branches.

References

• src/Serializer/AbstractItemNormalizer.php — vulnerable relation IRI load
• src/Symfony/Routing/IriConverter.php — conditional is_a guard (operation-aware path)

Credit

Reported by @alexandre-daubois.

Impact

#[ApiProperty(security: ...)] is evaluated per request to decide whether a property is exposed. The componentsCache arrays in ApiPlatform\JsonApi\Serializer\ItemNormalizer and ApiPlatform\Hal\Serializer\ItemNormalizer are keyed on $context['cache_key'], which is set unconditionally before delegating to the parent normalizer. The component structure (attributes, relationships, links) computed for one request can therefore be reused for a subsequent request whose user has a different set of accessible properties. A user with lower privileges may end up seeing the structure of properties that the security predicate would otherwise have hidden for them.

This is the same vulnerability class as GHSA-428q-q3vv-3fq3 / CVE-2025-31485, which fixed only the GraphQL ItemNormalizer. The JSON:API and HAL paths were not addressed at the time.

Exploitation conditions

Exploitation requires all of the following to coincide:

• The application exposes a resource via the JSON:API and/or HAL formats.
• At least one property of that resource uses #[ApiProperty(security: ...)] with a predicate whose result depends on the current user (or on per-request state).
• A request from a user for whom the predicate evaluates to true populates componentsCache before a request from a user for whom the predicate evaluates to false, within the lifetime of the same PHP process.
• The deployment uses a long-running PHP runtime that keeps the normalizer instance alive across requests (FrankenPHP worker mode, RoadRunner, Swoole, ReactPHP, etc.). With classic php-fpm workers the cache only survives the duration of a single request, which makes the issue much harder to observe in practice.

Patches

• 4.1.29
• 4.2.25
• 4.3.8

All three branches receive patched releases of api-platform/core, api-platform/json-api, and api-platform/hal.

Workarounds

Override the JSON:API and HAL ItemNormalizer services to gate $context['cache_key'] with a resource-class security check, or avoid #[ApiProperty(security: ...)] on resources served as JSON:API or HAL until the patch is applied. Pinning the deployment to classic php-fpm workers also limits exposure since the cache does not survive across requests.

Credits

• Tillmann Baumgart (@tillmon) — originally identified the broader cache-key gap and proposed moving isCacheKeySafe to AbstractItemNormalizer.
• Antoine Bluchet (@soyuka) — extended the gate to JSON:API and HAL normalizers.

Summary

The API Platform serializer's AbstractItemNormalizer does not validate the resource type returned when resolving relation IRIs, allowing type confusion where a resource of an unintended type can be silently assigned to a relation property.

Impact

An attacker who can submit write requests (POST/PUT/PATCH) to an API Platform endpoint with writable relations can supply a relation IRI pointing to a resource of a different type than the relation's declared class. Because getResourceFromIri() does not pass an $operation to IriConverter::getResourceFromIri(), the is_a type guard at IriConverter.php:86 is skipped. For untyped relation properties (legacy @var-only style), the wrong-typed object is silently assigned, corrupting invariants and potentially feeding downstream logic that assumes the declared type (CWE-843). For typed properties (modern PHP 8.x), the substitution is blocked by Symfony's PropertyAccessor with an InvalidTypeException.

Affected versions

• api-platform/core < 4.1.30
• api-platform/core >= 4.2.0, < 4.2.26
• api-platform/core >= 4.3.0, < 4.3.12

Older major series (2.x, 3.x) ship the same vulnerable code path and are end-of-life; no fix is planned.

Patched versions

• 4.1.30
• 4.2.26
• 4.3.12

Fix

An is_a guard is added inside AbstractItemNormalizer::getResourceFromIri() (and the equivalent inline call sites on 4.1) so that a mismatched IRI throws InvalidArgumentException, mirroring the operation-aware check the IriConverter already performs when an operation is supplied. This forces a 400 Bad Request response for cross-type IRIs instead of a silent assignment.

Workarounds

Declare a PHP type on every writable relation property (e.g. public ?Foo $relation = null; instead of @var Foo $relation). Symfony's PropertyAccessor will then reject a mismatched object with InvalidTypeException. This does not cover collections of mixed-type interfaces; upgrading to a patched version is the only complete fix.

Proof of concept

A functional test posts a Bar IRI to a Foo-declared relation on an untyped property. Without the fix the server responds with HTTP 201 and the Bar IRI appears in the response payload. With the fix the server responds with HTTP 400 (Invalid IRI "/bars/1").

Full PoC: tests/Functional/Security/TypeConfusionRelationIriTest.php in the patched branches.

References

• src/Serializer/AbstractItemNormalizer.php — vulnerable relation IRI load
• src/Symfony/Routing/IriConverter.php — conditional is_a guard (operation-aware path)

Credit

Reported by @alexandre-daubois.

Impact

#[ApiProperty(security: ...)] is evaluated per request to decide whether a property is exposed. The componentsCache arrays in ApiPlatform\JsonApi\Serializer\ItemNormalizer and ApiPlatform\Hal\Serializer\ItemNormalizer are keyed on $context['cache_key'], which is set unconditionally before delegating to the parent normalizer. The component structure (attributes, relationships, links) computed for one request can therefore be reused for a subsequent request whose user has a different set of accessible properties. A user with lower privileges may end up seeing the structure of properties that the security predicate would otherwise have hidden for them.

This is the same vulnerability class as GHSA-428q-q3vv-3fq3 / CVE-2025-31485, which fixed only the GraphQL ItemNormalizer. The JSON:API and HAL paths were not addressed at the time.

Exploitation conditions

Exploitation requires all of the following to coincide:

• The application exposes a resource via the JSON:API and/or HAL formats.
• At least one property of that resource uses #[ApiProperty(security: ...)] with a predicate whose result depends on the current user (or on per-request state).
• A request from a user for whom the predicate evaluates to true populates componentsCache before a request from a user for whom the predicate evaluates to false, within the lifetime of the same PHP process.
• The deployment uses a long-running PHP runtime that keeps the normalizer instance alive across requests (FrankenPHP worker mode, RoadRunner, Swoole, ReactPHP, etc.). With classic php-fpm workers the cache only survives the duration of a single request, which makes the issue much harder to observe in practice.

Patches

• 4.1.29
• 4.2.25
• 4.3.8

All three branches receive patched releases of api-platform/core, api-platform/json-api, and api-platform/hal.

Workarounds

Override the JSON:API and HAL ItemNormalizer services to gate $context['cache_key'] with a resource-class security check, or avoid #[ApiProperty(security: ...)] on resources served as JSON:API or HAL until the patch is applied. Pinning the deployment to classic php-fpm workers also limits exposure since the cache does not survive across requests.

Credits

• Tillmann Baumgart (@tillmon) — originally identified the broader cache-key gap and proposed moving isCacheKeySafe to AbstractItemNormalizer.
• Antoine Bluchet (@soyuka) — extended the gate to JSON:API and HAL normalizers.

Summary

The API Platform serializer's AbstractItemNormalizer does not validate the resource type returned when resolving relation IRIs, allowing type confusion where a resource of an unintended type can be silently assigned to a relation property.

Impact

An attacker who can submit write requests (POST/PUT/PATCH) to an API Platform endpoint with writable relations can supply a relation IRI pointing to a resource of a different type than the relation's declared class. Because getResourceFromIri() does not pass an $operation to IriConverter::getResourceFromIri(), the is_a type guard at IriConverter.php:86 is skipped. For untyped relation properties (legacy @var-only style), the wrong-typed object is silently assigned, corrupting invariants and potentially feeding downstream logic that assumes the declared type (CWE-843). For typed properties (modern PHP 8.x), the substitution is blocked by Symfony's PropertyAccessor with an InvalidTypeException.

Affected versions

• api-platform/core < 4.1.30
• api-platform/core >= 4.2.0, < 4.2.26
• api-platform/core >= 4.3.0, < 4.3.12

Older major series (2.x, 3.x) ship the same vulnerable code path and are end-of-life; no fix is planned.

Patched versions

• 4.1.30
• 4.2.26
• 4.3.12

Fix

An is_a guard is added inside AbstractItemNormalizer::getResourceFromIri() (and the equivalent inline call sites on 4.1) so that a mismatched IRI throws InvalidArgumentException, mirroring the operation-aware check the IriConverter already performs when an operation is supplied. This forces a 400 Bad Request response for cross-type IRIs instead of a silent assignment.

Workarounds

Declare a PHP type on every writable relation property (e.g. public ?Foo $relation = null; instead of @var Foo $relation). Symfony's PropertyAccessor will then reject a mismatched object with InvalidTypeException. This does not cover collections of mixed-type interfaces; upgrading to a patched version is the only complete fix.

Proof of concept

A functional test posts a Bar IRI to a Foo-declared relation on an untyped property. Without the fix the server responds with HTTP 201 and the Bar IRI appears in the response payload. With the fix the server responds with HTTP 400 (Invalid IRI "/bars/1").

Full PoC: tests/Functional/Security/TypeConfusionRelationIriTest.php in the patched branches.

References

• src/Serializer/AbstractItemNormalizer.php — vulnerable relation IRI load
• src/Symfony/Routing/IriConverter.php — conditional is_a guard (operation-aware path)

Credit

Reported by @alexandre-daubois.

Impact

#[ApiProperty(security: ...)] is evaluated per request to decide whether a property is exposed. The componentsCache arrays in ApiPlatform\JsonApi\Serializer\ItemNormalizer and ApiPlatform\Hal\Serializer\ItemNormalizer are keyed on $context['cache_key'], which is set unconditionally before delegating to the parent normalizer. The component structure (attributes, relationships, links) computed for one request can therefore be reused for a subsequent request whose user has a different set of accessible properties. A user with lower privileges may end up seeing the structure of properties that the security predicate would otherwise have hidden for them.

This is the same vulnerability class as GHSA-428q-q3vv-3fq3 / CVE-2025-31485, which fixed only the GraphQL ItemNormalizer. The JSON:API and HAL paths were not addressed at the time.

Exploitation conditions

Exploitation requires all of the following to coincide:

• The application exposes a resource via the JSON:API and/or HAL formats.
• At least one property of that resource uses #[ApiProperty(security: ...)] with a predicate whose result depends on the current user (or on per-request state).
• A request from a user for whom the predicate evaluates to true populates componentsCache before a request from a user for whom the predicate evaluates to false, within the lifetime of the same PHP process.
• The deployment uses a long-running PHP runtime that keeps the normalizer instance alive across requests (FrankenPHP worker mode, RoadRunner, Swoole, ReactPHP, etc.). With classic php-fpm workers the cache only survives the duration of a single request, which makes the issue much harder to observe in practice.

Patches

• 4.1.29
• 4.2.25
• 4.3.8

All three branches receive patched releases of api-platform/core, api-platform/json-api, and api-platform/hal.

Workarounds

Override the JSON:API and HAL ItemNormalizer services to gate $context['cache_key'] with a resource-class security check, or avoid #[ApiProperty(security: ...)] on resources served as JSON:API or HAL until the patch is applied. Pinning the deployment to classic php-fpm workers also limits exposure since the cache does not survive across requests.

Credits

• Tillmann Baumgart (@tillmon) — originally identified the broader cache-key gap and proposed moving isCacheKeySafe to AbstractItemNormalizer.
• Antoine Bluchet (@soyuka) — extended the gate to JSON:API and HAL normalizers.

Summary

The API Platform serializer's AbstractItemNormalizer does not validate the resource type returned when resolving relation IRIs, allowing type confusion where a resource of an unintended type can be silently assigned to a relation property.

Impact

An attacker who can submit write requests (POST/PUT/PATCH) to an API Platform endpoint with writable relations can supply a relation IRI pointing to a resource of a different type than the relation's declared class. Because getResourceFromIri() does not pass an $operation to IriConverter::getResourceFromIri(), the is_a type guard at IriConverter.php:86 is skipped. For untyped relation properties (legacy @var-only style), the wrong-typed object is silently assigned, corrupting invariants and potentially feeding downstream logic that assumes the declared type (CWE-843). For typed properties (modern PHP 8.x), the substitution is blocked by Symfony's PropertyAccessor with an InvalidTypeException.

Affected versions

• api-platform/core < 4.1.30
• api-platform/core >= 4.2.0, < 4.2.26
• api-platform/core >= 4.3.0, < 4.3.12

Older major series (2.x, 3.x) ship the same vulnerable code path and are end-of-life; no fix is planned.

Patched versions

• 4.1.30
• 4.2.26
• 4.3.12

Fix

An is_a guard is added inside AbstractItemNormalizer::getResourceFromIri() (and the equivalent inline call sites on 4.1) so that a mismatched IRI throws InvalidArgumentException, mirroring the operation-aware check the IriConverter already performs when an operation is supplied. This forces a 400 Bad Request response for cross-type IRIs instead of a silent assignment.

Workarounds

Declare a PHP type on every writable relation property (e.g. public ?Foo $relation = null; instead of @var Foo $relation). Symfony's PropertyAccessor will then reject a mismatched object with InvalidTypeException. This does not cover collections of mixed-type interfaces; upgrading to a patched version is the only complete fix.

Proof of concept

A functional test posts a Bar IRI to a Foo-declared relation on an untyped property. Without the fix the server responds with HTTP 201 and the Bar IRI appears in the response payload. With the fix the server responds with HTTP 400 (Invalid IRI "/bars/1").

Full PoC: tests/Functional/Security/TypeConfusionRelationIriTest.php in the patched branches.

References

• src/Serializer/AbstractItemNormalizer.php — vulnerable relation IRI load
• src/Symfony/Routing/IriConverter.php — conditional is_a guard (operation-aware path)

Credit

Reported by @alexandre-daubois.

Impact

#[ApiProperty(security: ...)] is evaluated per request to decide whether a property is exposed. The componentsCache arrays in ApiPlatform\JsonApi\Serializer\ItemNormalizer and ApiPlatform\Hal\Serializer\ItemNormalizer are keyed on $context['cache_key'], which is set unconditionally before delegating to the parent normalizer. The component structure (attributes, relationships, links) computed for one request can therefore be reused for a subsequent request whose user has a different set of accessible properties. A user with lower privileges may end up seeing the structure of properties that the security predicate would otherwise have hidden for them.

This is the same vulnerability class as GHSA-428q-q3vv-3fq3 / CVE-2025-31485, which fixed only the GraphQL ItemNormalizer. The JSON:API and HAL paths were not addressed at the time.

Exploitation conditions

Exploitation requires all of the following to coincide:

• The application exposes a resource via the JSON:API and/or HAL formats.
• At least one property of that resource uses #[ApiProperty(security: ...)] with a predicate whose result depends on the current user (or on per-request state).
• A request from a user for whom the predicate evaluates to true populates componentsCache before a request from a user for whom the predicate evaluates to false, within the lifetime of the same PHP process.
• The deployment uses a long-running PHP runtime that keeps the normalizer instance alive across requests (FrankenPHP worker mode, RoadRunner, Swoole, ReactPHP, etc.). With classic php-fpm workers the cache only survives the duration of a single request, which makes the issue much harder to observe in practice.

Patches

• 4.1.29
• 4.2.25
• 4.3.8

All three branches receive patched releases of api-platform/core, api-platform/json-api, and api-platform/hal.

Workarounds

Override the JSON:API and HAL ItemNormalizer services to gate $context['cache_key'] with a resource-class security check, or avoid #[ApiProperty(security: ...)] on resources served as JSON:API or HAL until the patch is applied. Pinning the deployment to classic php-fpm workers also limits exposure since the cache does not survive across requests.

Credits

• Tillmann Baumgart (@tillmon) — originally identified the broader cache-key gap and proposed moving isCacheKeySafe to AbstractItemNormalizer.
• Antoine Bluchet (@soyuka) — extended the gate to JSON:API and HAL normalizers.

Summary

The API Platform serializer's AbstractItemNormalizer does not validate the resource type returned when resolving relation IRIs, allowing type confusion where a resource of an unintended type can be silently assigned to a relation property.

Impact

An attacker who can submit write requests (POST/PUT/PATCH) to an API Platform endpoint with writable relations can supply a relation IRI pointing to a resource of a different type than the relation's declared class. Because getResourceFromIri() does not pass an $operation to IriConverter::getResourceFromIri(), the is_a type guard at IriConverter.php:86 is skipped. For untyped relation properties (legacy @var-only style), the wrong-typed object is silently assigned, corrupting invariants and potentially feeding downstream logic that assumes the declared type (CWE-843). For typed properties (modern PHP 8.x), the substitution is blocked by Symfony's PropertyAccessor with an InvalidTypeException.

Affected versions

• api-platform/core < 4.1.30
• api-platform/core >= 4.2.0, < 4.2.26
• api-platform/core >= 4.3.0, < 4.3.12

Older major series (2.x, 3.x) ship the same vulnerable code path and are end-of-life; no fix is planned.

Patched versions

• 4.1.30
• 4.2.26
• 4.3.12

Fix

An is_a guard is added inside AbstractItemNormalizer::getResourceFromIri() (and the equivalent inline call sites on 4.1) so that a mismatched IRI throws InvalidArgumentException, mirroring the operation-aware check the IriConverter already performs when an operation is supplied. This forces a 400 Bad Request response for cross-type IRIs instead of a silent assignment.

Workarounds

Declare a PHP type on every writable relation property (e.g. public ?Foo $relation = null; instead of @var Foo $relation). Symfony's PropertyAccessor will then reject a mismatched object with InvalidTypeException. This does not cover collections of mixed-type interfaces; upgrading to a patched version is the only complete fix.

Proof of concept

A functional test posts a Bar IRI to a Foo-declared relation on an untyped property. Without the fix the server responds with HTTP 201 and the Bar IRI appears in the response payload. With the fix the server responds with HTTP 400 (Invalid IRI "/bars/1").

Full PoC: tests/Functional/Security/TypeConfusionRelationIriTest.php in the patched branches.

References

• src/Serializer/AbstractItemNormalizer.php — vulnerable relation IRI load
• src/Symfony/Routing/IriConverter.php — conditional is_a guard (operation-aware path)

Credit

Reported by @alexandre-daubois.