CVE-2026-88004
highTraefik is an open source HTTP reverse proxy and load balancer.
Vendor / product: Traefik — traefik
Traefik is an open source HTTP reverse proxy and load balancer. From 3.2.0 until 3.7.13, Traefik entrypoint defenses aliasHeadersStrategy, underscoreHeadersStrategy, and forwardedHeaders inspect req.Header but not req.Trailer, allowing an unauthenticated client to submit an aliasing or trusted header name in an HTTP/1.1 chunked trailer or an HTTP/2 trailer. When the retry or buffering middleware reads the body before the reverse proxy clones the request, the attacker-controlled trailer value reaches a backend that merges trailers into the header namespace, bypassing the documented delete or reject behavior and potentially spoofing identity or forwarded routing data. This issue is fixed in 3.7.13.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N Affected products
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
References
- https://github.com/traefik/traefik/commit/55bbda4f65e0f9c533c870983a767a7081126db7 security-advisories@github.com
- https://github.com/traefik/traefik/pull/13822 security-advisories@github.com
- https://github.com/traefik/traefik/releases/tag/v3.7.13 security-advisories@github.com
- https://github.com/traefik/traefik/security/advisories/GHSA-v67p-phpq-fc8x security-advisories@github.com