{"id":"CVE-2026-88008","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-88008","summary":"Traefik is an open source HTTP reverse proxy and load balancer. From 2.11.26 until 2.11.57 and 3.7.13, Traefik forwards a client-supplied Connection header requesting Upgrade, the Upgrade:…","details":"Traefik is an open source HTTP reverse proxy and load balancer. From 2.11.26 until 2.11.57 and 3.7.13, Traefik forwards a client-supplied Connection header requesting Upgrade, the Upgrade: h2c token, and HTTP2-Settings to a shared backend. If the backend accepts h2c and returns 101 Switching Protocols, Traefik enters a raw tunnel and no longer applies routers, BasicAuth, ForwardAuth, IPAllowList, RateLimit, access logging, metrics, or tracing to later HTTP/2 requests, allowing an unauthenticated request through an unprotected route to reach protected paths on the same backend. This issue is fixed in 2.11.57 and 3.7.13.","published":"2026-09-10T15:17:56.433","modified":"2026-09-10T15:17:56.433","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":{"url":"https://github.com/traefik/traefik/commit/a277e94664ffc1ce9543df552d3bbf48d4d3b8b3","label":"traefik/traefik@a277e94"},"references":[{"type":"WEB","url":"https://github.com/traefik/traefik/commit/a277e94664ffc1ce9543df552d3bbf48d4d3b8b3"},{"type":"WEB","url":"https://github.com/traefik/traefik/pull/13797"},{"type":"WEB","url":"https://github.com/traefik/traefik/releases/tag/v2.11.57"},{"type":"WEB","url":"https://github.com/traefik/traefik/releases/tag/v3.7.13"},{"type":"WEB","url":"https://github.com/traefik/traefik/security/advisories/GHSA-w4v4-9rw7-5326"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-09-10T15:17:56.433"}}