pingora-core

Impact

Pingora versions prior to 0.8.0 improperly allowed HTTP/1.0 request bodies to be close-delimited and incorrectly handled multiple Transfer-Encoding values. This allows an attacker to desync Pingora's request framing from backend servers and smuggle requests to the backend.

This vulnerability primarily affects standalone Pingora deployments in front of certain backends that accept HTTP/1.0 requests. An attacker could exploit this to bypass proxy-level ACL controls and WAF logic, poison caches and upstream connections, or perform cross-user attacks by hijacking sessions.

Note: Cloudflare customers and Cloudflare's CDN infrastructure were not affected by this vulnerability, as its ingress proxy layers rejected ambiguous framing such as invalid Content-Length values and internally forwarded non-ambiguous message length framing headers.

Patches

Pingora users should upgrade to Pingora v0.8.0 or higher that fixes this issue by correctly parsing message length headers per RFC 9112 and strictly adhering to more RFC guidelines, including that HTTP request bodies are never close-delimited (commits 7f7166d62fa916b9f11b2eb8f9e3c4999e8b9023, 40c3c1e9a43a86b38adeab8da7a2f6eba68b83ad, and 87e2e2fb37edf9be33e3b1d04726293ae6bf2052).

Workarounds

As a workaround, users can reject certain requests with an error in the request filter logic in order to stop processing bytes on the connection and disable downstream connection reuse. The user should reject any non-HTTP/1.1 request, or a request that has invalid Content-Length, multiple Transfer-Encoding headers, or Transfer-Encoding header that is not an exact “chunked” string match.

References

See CVE-2026-2835 and the Cloudflare blog post for more details.

Credits

Disclosed responsibly by Rajat Raghav (@xclow3n) through the Cloudflare Bug Bounty Program.

Impact

Pingora versions prior to 0.8.0 would immediately forward bytes following a request with an Upgrade header to the backend, without waiting for a 101 Switching Protocols response. This allows an attacker to smuggle requests to the backend and bypass proxy-level security controls.

This vulnerability primarily affects standalone Pingora deployments where a Pingora proxy is exposed to external traffic. An attacker could exploit this to bypass proxy-level ACL controls and WAF logic, poison caches and upstream connections, or perform cross-user attacks by hijacking sessions.

Note: Cloudflare customers and Cloudflare's CDN infrastructure were not affected by this vulnerability, as ingress proxies in the CDN stack maintain proper HTTP parsing boundaries and do not prematurely switch to upgraded connection forwarding mode.

Patches

Pingora users should upgrade to Pingora v0.8.0 or higher, which fixes this issue by only switching connection modes after receiving a 101 Switching Protocols response from the backend (hash 824bdeefc61e121cc8861de1b35e8e8f39026ecd). Without a 101 response, subsequent bytes continue to be parsed as HTTP requests.

Workarounds

As a workaround, users may return an error on requests with the Upgrade header present in their request filter logic in order to stop processing bytes beyond the request header and disable downstream connection reuse.

References

See CVE-2026-2833 and the Cloudflare blog post for more details.

Credits

Disclosed responsibly by Rajat Raghav (@xclow3n) through the Cloudflare Bug Bounty Program.

Impact

Pingora versions prior to 0.8.0 improperly allowed HTTP/1.0 request bodies to be close-delimited and incorrectly handled multiple Transfer-Encoding values. This allows an attacker to desync Pingora's request framing from backend servers and smuggle requests to the backend.

This vulnerability primarily affects standalone Pingora deployments in front of certain backends that accept HTTP/1.0 requests. An attacker could exploit this to bypass proxy-level ACL controls and WAF logic, poison caches and upstream connections, or perform cross-user attacks by hijacking sessions.

Note: Cloudflare customers and Cloudflare's CDN infrastructure were not affected by this vulnerability, as its ingress proxy layers rejected ambiguous framing such as invalid Content-Length values and internally forwarded non-ambiguous message length framing headers.

Patches

Pingora users should upgrade to Pingora v0.8.0 or higher that fixes this issue by correctly parsing message length headers per RFC 9112 and strictly adhering to more RFC guidelines, including that HTTP request bodies are never close-delimited (commits 7f7166d62fa916b9f11b2eb8f9e3c4999e8b9023, 40c3c1e9a43a86b38adeab8da7a2f6eba68b83ad, and 87e2e2fb37edf9be33e3b1d04726293ae6bf2052).

Workarounds

As a workaround, users can reject certain requests with an error in the request filter logic in order to stop processing bytes on the connection and disable downstream connection reuse. The user should reject any non-HTTP/1.1 request, or a request that has invalid Content-Length, multiple Transfer-Encoding headers, or Transfer-Encoding header that is not an exact “chunked” string match.

References

See CVE-2026-2835 and the Cloudflare blog post for more details.

Credits

Disclosed responsibly by Rajat Raghav (@xclow3n) through the Cloudflare Bug Bounty Program.

Impact

Pingora versions prior to 0.8.0 would immediately forward bytes following a request with an Upgrade header to the backend, without waiting for a 101 Switching Protocols response. This allows an attacker to smuggle requests to the backend and bypass proxy-level security controls.

This vulnerability primarily affects standalone Pingora deployments where a Pingora proxy is exposed to external traffic. An attacker could exploit this to bypass proxy-level ACL controls and WAF logic, poison caches and upstream connections, or perform cross-user attacks by hijacking sessions.

Note: Cloudflare customers and Cloudflare's CDN infrastructure were not affected by this vulnerability, as ingress proxies in the CDN stack maintain proper HTTP parsing boundaries and do not prematurely switch to upgraded connection forwarding mode.

Patches

Pingora users should upgrade to Pingora v0.8.0 or higher, which fixes this issue by only switching connection modes after receiving a 101 Switching Protocols response from the backend (hash 824bdeefc61e121cc8861de1b35e8e8f39026ecd). Without a 101 response, subsequent bytes continue to be parsed as HTTP requests.

Workarounds

As a workaround, users may return an error on requests with the Upgrade header present in their request filter logic in order to stop processing bytes beyond the request header and disable downstream connection reuse.

References

See CVE-2026-2833 and the Cloudflare blog post for more details.

Credits

Disclosed responsibly by Rajat Raghav (@xclow3n) through the Cloudflare Bug Bounty Program.

Impact

Pingora versions prior to 0.8.0 improperly allowed HTTP/1.0 request bodies to be close-delimited and incorrectly handled multiple Transfer-Encoding values. This allows an attacker to desync Pingora's request framing from backend servers and smuggle requests to the backend.

This vulnerability primarily affects standalone Pingora deployments in front of certain backends that accept HTTP/1.0 requests. An attacker could exploit this to bypass proxy-level ACL controls and WAF logic, poison caches and upstream connections, or perform cross-user attacks by hijacking sessions.

Note: Cloudflare customers and Cloudflare's CDN infrastructure were not affected by this vulnerability, as its ingress proxy layers rejected ambiguous framing such as invalid Content-Length values and internally forwarded non-ambiguous message length framing headers.

Patches

Pingora users should upgrade to Pingora v0.8.0 or higher that fixes this issue by correctly parsing message length headers per RFC 9112 and strictly adhering to more RFC guidelines, including that HTTP request bodies are never close-delimited (commits 7f7166d62fa916b9f11b2eb8f9e3c4999e8b9023, 40c3c1e9a43a86b38adeab8da7a2f6eba68b83ad, and 87e2e2fb37edf9be33e3b1d04726293ae6bf2052).

Workarounds

As a workaround, users can reject certain requests with an error in the request filter logic in order to stop processing bytes on the connection and disable downstream connection reuse. The user should reject any non-HTTP/1.1 request, or a request that has invalid Content-Length, multiple Transfer-Encoding headers, or Transfer-Encoding header that is not an exact “chunked” string match.

References

See CVE-2026-2835 and the Cloudflare blog post for more details.

Credits

Disclosed responsibly by Rajat Raghav (@xclow3n) through the Cloudflare Bug Bounty Program.

Impact

Pingora versions prior to 0.8.0 would immediately forward bytes following a request with an Upgrade header to the backend, without waiting for a 101 Switching Protocols response. This allows an attacker to smuggle requests to the backend and bypass proxy-level security controls.

This vulnerability primarily affects standalone Pingora deployments where a Pingora proxy is exposed to external traffic. An attacker could exploit this to bypass proxy-level ACL controls and WAF logic, poison caches and upstream connections, or perform cross-user attacks by hijacking sessions.

Note: Cloudflare customers and Cloudflare's CDN infrastructure were not affected by this vulnerability, as ingress proxies in the CDN stack maintain proper HTTP parsing boundaries and do not prematurely switch to upgraded connection forwarding mode.

Patches

Pingora users should upgrade to Pingora v0.8.0 or higher, which fixes this issue by only switching connection modes after receiving a 101 Switching Protocols response from the backend (hash 824bdeefc61e121cc8861de1b35e8e8f39026ecd). Without a 101 response, subsequent bytes continue to be parsed as HTTP requests.

Workarounds

As a workaround, users may return an error on requests with the Upgrade header present in their request filter logic in order to stop processing bytes beyond the request header and disable downstream connection reuse.

References

See CVE-2026-2833 and the Cloudflare blog post for more details.

Credits

Disclosed responsibly by Rajat Raghav (@xclow3n) through the Cloudflare Bug Bounty Program.

Pingora deployments that include HTTP/2 server support may be affected by the vulnerability described in CVE-2025-8671. Under certain conditions, Pingora applications may allocate buffers before the HTTP/2 reset and resulting stream cancellation is processed by the server. Repeated resets can force excessive memory consumption and lead to denial-of-service.

Impact: On affected versions, malicious clients could trigger unusually high memory consumption, which may result in service instability or process termination.

Credits: Reported responsibly by security researcher Gal Bar Nahum (@galbarnahum)

Mitigation: This issue is addressed by ensuring Pingora uses patched versions of HTTP/2 dependencies that include reset-handling safeguards to release connection resources before excessive memory buildup. Users should upgrade to the latest Pingora release, which incorporates the required fixes.

• Users are requested to upgrade to latest version of Pingora >= 0.6.0

Pingora deployments using versions prior to 0.6.0 that include HTTP/2 server support may be affected by the vulnerability described in CVE-2025-8671. Under certain conditions, Pingora applications may allocate buffers before the HTTP/2 reset and resulting stream cancellation is processed by the server. Repeated resets can force excessive memory consumption and lead to denial-of-service.

On affected versions, malicious clients could trigger unusually high memory consumption, which may result in service instability or process termination.

This issue is addressed by ensuring Pingora uses patched versions of HTTP/2 dependencies that include reset-handling safeguards to release connection resources before excessive memory buildup. Users are requested to upgrade to versions >= 0.6.0, which incorporates the required fixes.

Impact

Pingora versions prior to 0.8.0 improperly allowed HTTP/1.0 request bodies to be close-delimited and incorrectly handled multiple Transfer-Encoding values. This allows an attacker to desync Pingora's request framing from backend servers and smuggle requests to the backend.

This vulnerability primarily affects standalone Pingora deployments in front of certain backends that accept HTTP/1.0 requests. An attacker could exploit this to bypass proxy-level ACL controls and WAF logic, poison caches and upstream connections, or perform cross-user attacks by hijacking sessions.

Note: Cloudflare customers and Cloudflare's CDN infrastructure were not affected by this vulnerability, as its ingress proxy layers rejected ambiguous framing such as invalid Content-Length values and internally forwarded non-ambiguous message length framing headers.

Patches

Pingora users should upgrade to Pingora v0.8.0 or higher that fixes this issue by correctly parsing message length headers per RFC 9112 and strictly adhering to more RFC guidelines, including that HTTP request bodies are never close-delimited (commits 7f7166d62fa916b9f11b2eb8f9e3c4999e8b9023, 40c3c1e9a43a86b38adeab8da7a2f6eba68b83ad, and 87e2e2fb37edf9be33e3b1d04726293ae6bf2052).

Workarounds

As a workaround, users can reject certain requests with an error in the request filter logic in order to stop processing bytes on the connection and disable downstream connection reuse. The user should reject any non-HTTP/1.1 request, or a request that has invalid Content-Length, multiple Transfer-Encoding headers, or Transfer-Encoding header that is not an exact “chunked” string match.

References

See CVE-2026-2835 and the Cloudflare blog post for more details.

Credits

Disclosed responsibly by Rajat Raghav (@xclow3n) through the Cloudflare Bug Bounty Program.

Impact

Pingora versions prior to 0.8.0 would immediately forward bytes following a request with an Upgrade header to the backend, without waiting for a 101 Switching Protocols response. This allows an attacker to smuggle requests to the backend and bypass proxy-level security controls.

This vulnerability primarily affects standalone Pingora deployments where a Pingora proxy is exposed to external traffic. An attacker could exploit this to bypass proxy-level ACL controls and WAF logic, poison caches and upstream connections, or perform cross-user attacks by hijacking sessions.

Note: Cloudflare customers and Cloudflare's CDN infrastructure were not affected by this vulnerability, as ingress proxies in the CDN stack maintain proper HTTP parsing boundaries and do not prematurely switch to upgraded connection forwarding mode.

Patches

Pingora users should upgrade to Pingora v0.8.0 or higher, which fixes this issue by only switching connection modes after receiving a 101 Switching Protocols response from the backend (hash 824bdeefc61e121cc8861de1b35e8e8f39026ecd). Without a 101 response, subsequent bytes continue to be parsed as HTTP requests.

Workarounds

As a workaround, users may return an error on requests with the Upgrade header present in their request filter logic in order to stop processing bytes beyond the request header and disable downstream connection reuse.

References

See CVE-2026-2833 and the Cloudflare blog post for more details.

Credits

Disclosed responsibly by Rajat Raghav (@xclow3n) through the Cloudflare Bug Bounty Program.

Pingora deployments that include HTTP/2 server support may be affected by the vulnerability described in CVE-2025-8671. Under certain conditions, Pingora applications may allocate buffers before the HTTP/2 reset and resulting stream cancellation is processed by the server. Repeated resets can force excessive memory consumption and lead to denial-of-service.

Impact: On affected versions, malicious clients could trigger unusually high memory consumption, which may result in service instability or process termination.

Credits: Reported responsibly by security researcher Gal Bar Nahum (@galbarnahum)

Mitigation: This issue is addressed by ensuring Pingora uses patched versions of HTTP/2 dependencies that include reset-handling safeguards to release connection resources before excessive memory buildup. Users should upgrade to the latest Pingora release, which incorporates the required fixes.

• Users are requested to upgrade to latest version of Pingora >= 0.6.0

Pingora deployments using versions prior to 0.6.0 that include HTTP/2 server support may be affected by the vulnerability described in CVE-2025-8671. Under certain conditions, Pingora applications may allocate buffers before the HTTP/2 reset and resulting stream cancellation is processed by the server. Repeated resets can force excessive memory consumption and lead to denial-of-service.

On affected versions, malicious clients could trigger unusually high memory consumption, which may result in service instability or process termination.

This issue is addressed by ensuring Pingora uses patched versions of HTTP/2 dependencies that include reset-handling safeguards to release connection resources before excessive memory buildup. Users are requested to upgrade to versions >= 0.6.0, which incorporates the required fixes.

A request smuggling vulnerability identified within Pingora’s proxying framework, pingora-proxy, allows malicious HTTP requests to be injected via manipulated request bodies on cache HITs, leading to unauthorized request execution and potential cache poisoning.

Fixed in

https://github.com/cloudflare/pingora/commit/fda3317ec822678564d641e7cf1c9b77ee3759ff

Impact

The issue could lead to request smuggling in cases where Pingora’s proxying framework, pingora-proxy, is used for caching allowing an attacker to manipulate headers and URLs in subsequent requests made on the same HTTP/1.1 connection.

Impact

Pingora versions prior to 0.8.0 improperly allowed HTTP/1.0 request bodies to be close-delimited and incorrectly handled multiple Transfer-Encoding values. This allows an attacker to desync Pingora's request framing from backend servers and smuggle requests to the backend.

This vulnerability primarily affects standalone Pingora deployments in front of certain backends that accept HTTP/1.0 requests. An attacker could exploit this to bypass proxy-level ACL controls and WAF logic, poison caches and upstream connections, or perform cross-user attacks by hijacking sessions.

Note: Cloudflare customers and Cloudflare's CDN infrastructure were not affected by this vulnerability, as its ingress proxy layers rejected ambiguous framing such as invalid Content-Length values and internally forwarded non-ambiguous message length framing headers.

Patches

Pingora users should upgrade to Pingora v0.8.0 or higher that fixes this issue by correctly parsing message length headers per RFC 9112 and strictly adhering to more RFC guidelines, including that HTTP request bodies are never close-delimited (commits 7f7166d62fa916b9f11b2eb8f9e3c4999e8b9023, 40c3c1e9a43a86b38adeab8da7a2f6eba68b83ad, and 87e2e2fb37edf9be33e3b1d04726293ae6bf2052).

Workarounds

As a workaround, users can reject certain requests with an error in the request filter logic in order to stop processing bytes on the connection and disable downstream connection reuse. The user should reject any non-HTTP/1.1 request, or a request that has invalid Content-Length, multiple Transfer-Encoding headers, or Transfer-Encoding header that is not an exact “chunked” string match.

References

See CVE-2026-2835 and the Cloudflare blog post for more details.

Credits

Disclosed responsibly by Rajat Raghav (@xclow3n) through the Cloudflare Bug Bounty Program.

Impact

Pingora versions prior to 0.8.0 would immediately forward bytes following a request with an Upgrade header to the backend, without waiting for a 101 Switching Protocols response. This allows an attacker to smuggle requests to the backend and bypass proxy-level security controls.

This vulnerability primarily affects standalone Pingora deployments where a Pingora proxy is exposed to external traffic. An attacker could exploit this to bypass proxy-level ACL controls and WAF logic, poison caches and upstream connections, or perform cross-user attacks by hijacking sessions.

Note: Cloudflare customers and Cloudflare's CDN infrastructure were not affected by this vulnerability, as ingress proxies in the CDN stack maintain proper HTTP parsing boundaries and do not prematurely switch to upgraded connection forwarding mode.

Patches

Pingora users should upgrade to Pingora v0.8.0 or higher, which fixes this issue by only switching connection modes after receiving a 101 Switching Protocols response from the backend (hash 824bdeefc61e121cc8861de1b35e8e8f39026ecd). Without a 101 response, subsequent bytes continue to be parsed as HTTP requests.

Workarounds

As a workaround, users may return an error on requests with the Upgrade header present in their request filter logic in order to stop processing bytes beyond the request header and disable downstream connection reuse.

References

See CVE-2026-2833 and the Cloudflare blog post for more details.

Credits

Disclosed responsibly by Rajat Raghav (@xclow3n) through the Cloudflare Bug Bounty Program.

Pingora deployments that include HTTP/2 server support may be affected by the vulnerability described in CVE-2025-8671. Under certain conditions, Pingora applications may allocate buffers before the HTTP/2 reset and resulting stream cancellation is processed by the server. Repeated resets can force excessive memory consumption and lead to denial-of-service.

Impact: On affected versions, malicious clients could trigger unusually high memory consumption, which may result in service instability or process termination.

Credits: Reported responsibly by security researcher Gal Bar Nahum (@galbarnahum)

Mitigation: This issue is addressed by ensuring Pingora uses patched versions of HTTP/2 dependencies that include reset-handling safeguards to release connection resources before excessive memory buildup. Users should upgrade to the latest Pingora release, which incorporates the required fixes.

• Users are requested to upgrade to latest version of Pingora >= 0.6.0

Pingora deployments using versions prior to 0.6.0 that include HTTP/2 server support may be affected by the vulnerability described in CVE-2025-8671. Under certain conditions, Pingora applications may allocate buffers before the HTTP/2 reset and resulting stream cancellation is processed by the server. Repeated resets can force excessive memory consumption and lead to denial-of-service.

On affected versions, malicious clients could trigger unusually high memory consumption, which may result in service instability or process termination.

This issue is addressed by ensuring Pingora uses patched versions of HTTP/2 dependencies that include reset-handling safeguards to release connection resources before excessive memory buildup. Users are requested to upgrade to versions >= 0.6.0, which incorporates the required fixes.

A request smuggling vulnerability identified within Pingora’s proxying framework, pingora-proxy, allows malicious HTTP requests to be injected via manipulated request bodies on cache HITs, leading to unauthorized request execution and potential cache poisoning.

Fixed in

https://github.com/cloudflare/pingora/commit/fda3317ec822678564d641e7cf1c9b77ee3759ff

Impact

The issue could lead to request smuggling in cases where Pingora’s proxying framework, pingora-proxy, is used for caching allowing an attacker to manipulate headers and URLs in subsequent requests made on the same HTTP/1.1 connection.

Impact

Pingora versions prior to 0.8.0 improperly allowed HTTP/1.0 request bodies to be close-delimited and incorrectly handled multiple Transfer-Encoding values. This allows an attacker to desync Pingora's request framing from backend servers and smuggle requests to the backend.

This vulnerability primarily affects standalone Pingora deployments in front of certain backends that accept HTTP/1.0 requests. An attacker could exploit this to bypass proxy-level ACL controls and WAF logic, poison caches and upstream connections, or perform cross-user attacks by hijacking sessions.

Note: Cloudflare customers and Cloudflare's CDN infrastructure were not affected by this vulnerability, as its ingress proxy layers rejected ambiguous framing such as invalid Content-Length values and internally forwarded non-ambiguous message length framing headers.

Patches

Pingora users should upgrade to Pingora v0.8.0 or higher that fixes this issue by correctly parsing message length headers per RFC 9112 and strictly adhering to more RFC guidelines, including that HTTP request bodies are never close-delimited (commits 7f7166d62fa916b9f11b2eb8f9e3c4999e8b9023, 40c3c1e9a43a86b38adeab8da7a2f6eba68b83ad, and 87e2e2fb37edf9be33e3b1d04726293ae6bf2052).

Workarounds

As a workaround, users can reject certain requests with an error in the request filter logic in order to stop processing bytes on the connection and disable downstream connection reuse. The user should reject any non-HTTP/1.1 request, or a request that has invalid Content-Length, multiple Transfer-Encoding headers, or Transfer-Encoding header that is not an exact “chunked” string match.

References

See CVE-2026-2835 and the Cloudflare blog post for more details.

Credits

Disclosed responsibly by Rajat Raghav (@xclow3n) through the Cloudflare Bug Bounty Program.

Impact

Pingora versions prior to 0.8.0 would immediately forward bytes following a request with an Upgrade header to the backend, without waiting for a 101 Switching Protocols response. This allows an attacker to smuggle requests to the backend and bypass proxy-level security controls.

This vulnerability primarily affects standalone Pingora deployments where a Pingora proxy is exposed to external traffic. An attacker could exploit this to bypass proxy-level ACL controls and WAF logic, poison caches and upstream connections, or perform cross-user attacks by hijacking sessions.

Note: Cloudflare customers and Cloudflare's CDN infrastructure were not affected by this vulnerability, as ingress proxies in the CDN stack maintain proper HTTP parsing boundaries and do not prematurely switch to upgraded connection forwarding mode.

Patches

Pingora users should upgrade to Pingora v0.8.0 or higher, which fixes this issue by only switching connection modes after receiving a 101 Switching Protocols response from the backend (hash 824bdeefc61e121cc8861de1b35e8e8f39026ecd). Without a 101 response, subsequent bytes continue to be parsed as HTTP requests.

Workarounds

As a workaround, users may return an error on requests with the Upgrade header present in their request filter logic in order to stop processing bytes beyond the request header and disable downstream connection reuse.

References

See CVE-2026-2833 and the Cloudflare blog post for more details.

Credits

Disclosed responsibly by Rajat Raghav (@xclow3n) through the Cloudflare Bug Bounty Program.

Pingora deployments that include HTTP/2 server support may be affected by the vulnerability described in CVE-2025-8671. Under certain conditions, Pingora applications may allocate buffers before the HTTP/2 reset and resulting stream cancellation is processed by the server. Repeated resets can force excessive memory consumption and lead to denial-of-service.

Impact: On affected versions, malicious clients could trigger unusually high memory consumption, which may result in service instability or process termination.

Credits: Reported responsibly by security researcher Gal Bar Nahum (@galbarnahum)

Mitigation: This issue is addressed by ensuring Pingora uses patched versions of HTTP/2 dependencies that include reset-handling safeguards to release connection resources before excessive memory buildup. Users should upgrade to the latest Pingora release, which incorporates the required fixes.

• Users are requested to upgrade to latest version of Pingora >= 0.6.0

Pingora deployments using versions prior to 0.6.0 that include HTTP/2 server support may be affected by the vulnerability described in CVE-2025-8671. Under certain conditions, Pingora applications may allocate buffers before the HTTP/2 reset and resulting stream cancellation is processed by the server. Repeated resets can force excessive memory consumption and lead to denial-of-service.

On affected versions, malicious clients could trigger unusually high memory consumption, which may result in service instability or process termination.

This issue is addressed by ensuring Pingora uses patched versions of HTTP/2 dependencies that include reset-handling safeguards to release connection resources before excessive memory buildup. Users are requested to upgrade to versions >= 0.6.0, which incorporates the required fixes.

A request smuggling vulnerability identified within Pingora’s proxying framework, pingora-proxy, allows malicious HTTP requests to be injected via manipulated request bodies on cache HITs, leading to unauthorized request execution and potential cache poisoning.

Fixed in

https://github.com/cloudflare/pingora/commit/fda3317ec822678564d641e7cf1c9b77ee3759ff

Impact

The issue could lead to request smuggling in cases where Pingora’s proxying framework, pingora-proxy, is used for caching allowing an attacker to manipulate headers and URLs in subsequent requests made on the same HTTP/1.1 connection.

Impact

Pingora versions prior to 0.8.0 improperly allowed HTTP/1.0 request bodies to be close-delimited and incorrectly handled multiple Transfer-Encoding values. This allows an attacker to desync Pingora's request framing from backend servers and smuggle requests to the backend.

This vulnerability primarily affects standalone Pingora deployments in front of certain backends that accept HTTP/1.0 requests. An attacker could exploit this to bypass proxy-level ACL controls and WAF logic, poison caches and upstream connections, or perform cross-user attacks by hijacking sessions.

Note: Cloudflare customers and Cloudflare's CDN infrastructure were not affected by this vulnerability, as its ingress proxy layers rejected ambiguous framing such as invalid Content-Length values and internally forwarded non-ambiguous message length framing headers.

Patches

Pingora users should upgrade to Pingora v0.8.0 or higher that fixes this issue by correctly parsing message length headers per RFC 9112 and strictly adhering to more RFC guidelines, including that HTTP request bodies are never close-delimited (commits 7f7166d62fa916b9f11b2eb8f9e3c4999e8b9023, 40c3c1e9a43a86b38adeab8da7a2f6eba68b83ad, and 87e2e2fb37edf9be33e3b1d04726293ae6bf2052).

Workarounds

As a workaround, users can reject certain requests with an error in the request filter logic in order to stop processing bytes on the connection and disable downstream connection reuse. The user should reject any non-HTTP/1.1 request, or a request that has invalid Content-Length, multiple Transfer-Encoding headers, or Transfer-Encoding header that is not an exact “chunked” string match.

References

See CVE-2026-2835 and the Cloudflare blog post for more details.

Credits

Disclosed responsibly by Rajat Raghav (@xclow3n) through the Cloudflare Bug Bounty Program.

Impact

Pingora versions prior to 0.8.0 would immediately forward bytes following a request with an Upgrade header to the backend, without waiting for a 101 Switching Protocols response. This allows an attacker to smuggle requests to the backend and bypass proxy-level security controls.

This vulnerability primarily affects standalone Pingora deployments where a Pingora proxy is exposed to external traffic. An attacker could exploit this to bypass proxy-level ACL controls and WAF logic, poison caches and upstream connections, or perform cross-user attacks by hijacking sessions.

Note: Cloudflare customers and Cloudflare's CDN infrastructure were not affected by this vulnerability, as ingress proxies in the CDN stack maintain proper HTTP parsing boundaries and do not prematurely switch to upgraded connection forwarding mode.

Patches

Pingora users should upgrade to Pingora v0.8.0 or higher, which fixes this issue by only switching connection modes after receiving a 101 Switching Protocols response from the backend (hash 824bdeefc61e121cc8861de1b35e8e8f39026ecd). Without a 101 response, subsequent bytes continue to be parsed as HTTP requests.

Workarounds

As a workaround, users may return an error on requests with the Upgrade header present in their request filter logic in order to stop processing bytes beyond the request header and disable downstream connection reuse.

References

See CVE-2026-2833 and the Cloudflare blog post for more details.

Credits

Disclosed responsibly by Rajat Raghav (@xclow3n) through the Cloudflare Bug Bounty Program.

Pingora deployments that include HTTP/2 server support may be affected by the vulnerability described in CVE-2025-8671. Under certain conditions, Pingora applications may allocate buffers before the HTTP/2 reset and resulting stream cancellation is processed by the server. Repeated resets can force excessive memory consumption and lead to denial-of-service.

Impact: On affected versions, malicious clients could trigger unusually high memory consumption, which may result in service instability or process termination.

Credits: Reported responsibly by security researcher Gal Bar Nahum (@galbarnahum)

Mitigation: This issue is addressed by ensuring Pingora uses patched versions of HTTP/2 dependencies that include reset-handling safeguards to release connection resources before excessive memory buildup. Users should upgrade to the latest Pingora release, which incorporates the required fixes.

• Users are requested to upgrade to latest version of Pingora >= 0.6.0

Pingora deployments using versions prior to 0.6.0 that include HTTP/2 server support may be affected by the vulnerability described in CVE-2025-8671. Under certain conditions, Pingora applications may allocate buffers before the HTTP/2 reset and resulting stream cancellation is processed by the server. Repeated resets can force excessive memory consumption and lead to denial-of-service.

On affected versions, malicious clients could trigger unusually high memory consumption, which may result in service instability or process termination.

This issue is addressed by ensuring Pingora uses patched versions of HTTP/2 dependencies that include reset-handling safeguards to release connection resources before excessive memory buildup. Users are requested to upgrade to versions >= 0.6.0, which incorporates the required fixes.

A request smuggling vulnerability identified within Pingora’s proxying framework, pingora-proxy, allows malicious HTTP requests to be injected via manipulated request bodies on cache HITs, leading to unauthorized request execution and potential cache poisoning.

Fixed in

https://github.com/cloudflare/pingora/commit/fda3317ec822678564d641e7cf1c9b77ee3759ff

Impact

The issue could lead to request smuggling in cases where Pingora’s proxying framework, pingora-proxy, is used for caching allowing an attacker to manipulate headers and URLs in subsequent requests made on the same HTTP/1.1 connection.

Impact

Pingora versions prior to 0.8.0 improperly allowed HTTP/1.0 request bodies to be close-delimited and incorrectly handled multiple Transfer-Encoding values. This allows an attacker to desync Pingora's request framing from backend servers and smuggle requests to the backend.

This vulnerability primarily affects standalone Pingora deployments in front of certain backends that accept HTTP/1.0 requests. An attacker could exploit this to bypass proxy-level ACL controls and WAF logic, poison caches and upstream connections, or perform cross-user attacks by hijacking sessions.

Note: Cloudflare customers and Cloudflare's CDN infrastructure were not affected by this vulnerability, as its ingress proxy layers rejected ambiguous framing such as invalid Content-Length values and internally forwarded non-ambiguous message length framing headers.

Patches

Pingora users should upgrade to Pingora v0.8.0 or higher that fixes this issue by correctly parsing message length headers per RFC 9112 and strictly adhering to more RFC guidelines, including that HTTP request bodies are never close-delimited (commits 7f7166d62fa916b9f11b2eb8f9e3c4999e8b9023, 40c3c1e9a43a86b38adeab8da7a2f6eba68b83ad, and 87e2e2fb37edf9be33e3b1d04726293ae6bf2052).

Workarounds

As a workaround, users can reject certain requests with an error in the request filter logic in order to stop processing bytes on the connection and disable downstream connection reuse. The user should reject any non-HTTP/1.1 request, or a request that has invalid Content-Length, multiple Transfer-Encoding headers, or Transfer-Encoding header that is not an exact “chunked” string match.

References

See CVE-2026-2835 and the Cloudflare blog post for more details.

Credits

Disclosed responsibly by Rajat Raghav (@xclow3n) through the Cloudflare Bug Bounty Program.

Impact

Pingora versions prior to 0.8.0 would immediately forward bytes following a request with an Upgrade header to the backend, without waiting for a 101 Switching Protocols response. This allows an attacker to smuggle requests to the backend and bypass proxy-level security controls.

This vulnerability primarily affects standalone Pingora deployments where a Pingora proxy is exposed to external traffic. An attacker could exploit this to bypass proxy-level ACL controls and WAF logic, poison caches and upstream connections, or perform cross-user attacks by hijacking sessions.

Note: Cloudflare customers and Cloudflare's CDN infrastructure were not affected by this vulnerability, as ingress proxies in the CDN stack maintain proper HTTP parsing boundaries and do not prematurely switch to upgraded connection forwarding mode.

Patches

Pingora users should upgrade to Pingora v0.8.0 or higher, which fixes this issue by only switching connection modes after receiving a 101 Switching Protocols response from the backend (hash 824bdeefc61e121cc8861de1b35e8e8f39026ecd). Without a 101 response, subsequent bytes continue to be parsed as HTTP requests.

Workarounds

As a workaround, users may return an error on requests with the Upgrade header present in their request filter logic in order to stop processing bytes beyond the request header and disable downstream connection reuse.

References

See CVE-2026-2833 and the Cloudflare blog post for more details.

Credits

Disclosed responsibly by Rajat Raghav (@xclow3n) through the Cloudflare Bug Bounty Program.

Pingora deployments that include HTTP/2 server support may be affected by the vulnerability described in CVE-2025-8671. Under certain conditions, Pingora applications may allocate buffers before the HTTP/2 reset and resulting stream cancellation is processed by the server. Repeated resets can force excessive memory consumption and lead to denial-of-service.

Impact: On affected versions, malicious clients could trigger unusually high memory consumption, which may result in service instability or process termination.

Credits: Reported responsibly by security researcher Gal Bar Nahum (@galbarnahum)

Mitigation: This issue is addressed by ensuring Pingora uses patched versions of HTTP/2 dependencies that include reset-handling safeguards to release connection resources before excessive memory buildup. Users should upgrade to the latest Pingora release, which incorporates the required fixes.

• Users are requested to upgrade to latest version of Pingora >= 0.6.0

Pingora deployments using versions prior to 0.6.0 that include HTTP/2 server support may be affected by the vulnerability described in CVE-2025-8671. Under certain conditions, Pingora applications may allocate buffers before the HTTP/2 reset and resulting stream cancellation is processed by the server. Repeated resets can force excessive memory consumption and lead to denial-of-service.

On affected versions, malicious clients could trigger unusually high memory consumption, which may result in service instability or process termination.

This issue is addressed by ensuring Pingora uses patched versions of HTTP/2 dependencies that include reset-handling safeguards to release connection resources before excessive memory buildup. Users are requested to upgrade to versions >= 0.6.0, which incorporates the required fixes.

A request smuggling vulnerability identified within Pingora’s proxying framework, pingora-proxy, allows malicious HTTP requests to be injected via manipulated request bodies on cache HITs, leading to unauthorized request execution and potential cache poisoning.

Fixed in

https://github.com/cloudflare/pingora/commit/fda3317ec822678564d641e7cf1c9b77ee3759ff

Impact

The issue could lead to request smuggling in cases where Pingora’s proxying framework, pingora-proxy, is used for caching allowing an attacker to manipulate headers and URLs in subsequent requests made on the same HTTP/1.1 connection.