CVE-2026-88004

Name of the Vulnerable Software and Affected Versions Traefik versions 3.2.0 through 3.7.12

Description Traefik entrypoint defenses aliasHeadersStrategy, underscoreHeadersStrategy, and forwardedHeaders inspect req.Header but fail to inspect req.Trailer. This allows an unauthenticated client to submit an aliasing or trusted header name within an HTTP/1.1 chunked trailer or an HTTP/2 trailer. If the retry or buffering middleware reads the body before the reverse proxy clones the request, the attacker-controlled trailer value can reach a backend that merges trailers into the header namespace. This bypasses the intended delete or reject behavior, potentially enabling the spoofing of identity or forwarded routing data.

Recommendations Update to version 3.7.13.