CVE-2026-88009

Description

Traefik is an open source HTTP reverse proxy and load balancer. Prior to 2.11.57, and 3.7.13, Traefik accepts a rootless HTTP/1 request target that Go stores in URL.Opaque while leaving URL.Path empty. The rewriteRequestBuilder path evaluates routing, path sanitization, forwardAuth, encodedCharacters, and access logging against a path normalized to / but forwards URL.Opaque verbatim to the backend, allowing cross-vhost routing bypass, path-scoped authorization bypass, and access-log evasion when the backend interprets the opaque target as a path. This issue is fixed in 2.11.57 and 3.7.13.

References

• https://github.com/traefik/traefik/commit/58d1e9ca204526823211e30fd4634101c59d58e9
• https://github.com/traefik/traefik/pull/13796
• https://github.com/traefik/traefik/releases/tag/v2.11.57
• https://github.com/traefik/traefik/releases/tag/v3.7.13
• https://github.com/traefik/traefik/security/advisories/GHSA-f52w-8j3h-j724