{"id":"CVE-2026-88008","title":"Traefik is an open source HTTP reverse proxy and load balancer","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: h2c token, and HTTP2-Settings to a shared backen…","severity":"critical","cvss":9.1,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","cwe":["CWE-444","CWE-863"],"vendor":"traefik","product":"traefik","affected":["traefik >= 2.11.26, < 2.11.57","traefik >= 3.4.2, < 3.7.13"],"patched":["traefik 3.7.13"],"published":"2026-09-10","updated":"2026-09-14","sourceUpdated":"2026-09-14T19:59:04.550","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-88008","references":[{"url":"https://github.com/traefik/traefik/commit/a277e94664ffc1ce9543df552d3bbf48d4d3b8b3","label":"security-advisories@github.com"},{"url":"https://github.com/traefik/traefik/pull/13797","label":"security-advisories@github.com"},{"url":"https://github.com/traefik/traefik/releases/tag/v2.11.57","label":"security-advisories@github.com"},{"url":"https://github.com/traefik/traefik/releases/tag/v3.7.13","label":"security-advisories@github.com"},{"url":"https://github.com/traefik/traefik/security/advisories/GHSA-w4v4-9rw7-5326","label":"security-advisories@github.com"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-88008"},{"url":"https://github.com/traefik/traefik"}],"tags":["nvd","cve.org","osv","go","score-dispute"],"epss":0.00341,"epssPercentile":0.27768,"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-09-10T16:54:44.054899Z"},"scores":{"nvd":9.1,"cna":7},"ingestedAt":"2026-09-11T14:42:19.869Z","aliases":["GHSA-w4v4-9rw7-5326","GO-2026-6468"],"ecosystem":"go","slug":"CVE-2026-88008","body":"## Overview\n\nTraefik 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.\n\n## Affected\n\n- `traefik >= 2.11.26, < 2.11.57`\n- `traefik >= 3.4.2, < 3.7.13`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `traefik 3.7.13`\n\n## Package advisory (CVE-2026-88008)\n\nAffected packages:\n\n- `github.com/traefik/traefik/v3 >= 3.4.2, < 3.7.13`\n- `github.com/traefik/traefik/v2 >= 2.11.26, < 2.11.57`\n\nPatched in:\n\n- `github.com/traefik/traefik/v3 3.7.13`\n- `github.com/traefik/traefik/v2 2.11.57`\n\nSource: https://osv.dev/vulnerability/GHSA-w4v4-9rw7-5326","depth":"midnight","depthScore":50,"depthScoreParts":{"impact":50.1,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":203224,"id":"CVE-2026-88008","ts":1789416896117,"field":"cvss","old":"7","new":"9.1"},{"seq":203223,"id":"CVE-2026-88008","ts":1789416896117,"field":"severity","old":"high","new":"critical"}]}