Vulnerability Description
Traefik is an open source HTTP reverse proxy and load balancer. Prior to 2.11.53, 3.6.24, and 3.7.9, Traefik's default HTTP reverse proxy forwards a plain HTTP/2 or HTTP/3 CONNECT request and its body to an HTTP/1.1 upstream through a shared net/http.Transport. When the upstream answers the CONNECT with a keep-alive non-2xx response and does not drain the body, Traefik returns the desynchronized backend socket to its shared pool and reuses it for other clients. An unauthenticated attacker can use this behavior to make a different client read the attacker's smuggled response, which can include authenticated or private content from another request. The ForwardAuth middleware with forwardBody true and preserveRequestMethod true can re-issue a CONNECT with the buffered body attached, exposing the auth-client pool to the same desynchronization. This issue is fixed in 2.11.53, 3.6.24, and 3.7.9.
Related Weaknesses (CWE)
References
- https://github.com/traefik/traefik/commit/04d36f28e4eae7535e96a6351dd9f7bfb48a30
- https://github.com/traefik/traefik/commit/0807b6d5dd1da8b2f7f4076ea2392b5437bf2a
- https://github.com/traefik/traefik/commit/94a7508817d180f0ab2f1eae93df48d4ab19ec
- https://github.com/traefik/traefik/pull/13542
- https://github.com/traefik/traefik/pull/13543
- https://github.com/traefik/traefik/pull/13556
- https://github.com/traefik/traefik/releases/tag/v2.11.53
- https://github.com/traefik/traefik/releases/tag/v3.6.24
- https://github.com/traefik/traefik/releases/tag/v3.7.9
- https://github.com/traefik/traefik/security/advisories/GHSA-3ccp-42pg-hgv6
FAQ
What is CVE-2026-71324?
CVE-2026-71324 is a documented vulnerability. Traefik is an open source HTTP reverse proxy and load balancer. Prior to 2.11.53, 3.6.24, and 3.7.9, Traefik's default HTTP reverse proxy forwards a plain HTTP/2 or HTTP/3 CONNECT request and its body...
How severe is CVE-2026-71324?
CVSS scoring is not yet available for CVE-2026-71324. Check NVD for updates.
Is there a patch for CVE-2026-71324?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.