{"id":"CVE-2026-88008","state":"PUBLISHED","title":"Traefik: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') and Incorrect Authorization","description":"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.","publishedAt":"2026-09-10T14:57:06.162Z","updatedAt":"2026-09-10T16:56:53.731Z","severity":{"score":7,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N","source":"GitHub_M"},"assigner":"GitHub_M","products":["traefik traefik"],"affected":[{"vendor":"traefik","product":"traefik","versions":[{"version":">= 2.11.26, < 2.11.57","status":"affected"},{"version":">= 3.4.2, < 3.7.13","status":"affected"}]}],"references":["https://github.com/traefik/traefik/security/advisories/GHSA-w4v4-9rw7-5326","https://github.com/traefik/traefik/pull/13797","https://github.com/traefik/traefik/commit/a277e94664ffc1ce9543df552d3bbf48d4d3b8b3","https://github.com/traefik/traefik/releases/tag/v2.11.57","https://github.com/traefik/traefik/releases/tag/v3.7.13"],"weaknesses":["CWE-444","CWE-863"],"ingestedAt":"2026-10-29T20:13:26.108Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/88xxx/CVE-2026-88008.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-88008","state":"PUBLISHED","datePublished":"2026-09-10T14:57:06.162Z","dateUpdated":"2026-09-10T16:56:53.731Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-09-09T19:19:27.406Z"},"containers":{"cna":{"title":"Traefik: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') and Incorrect Authorization","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"traefik","product":"traefik","versions":[{"version":">= 2.11.26, < 2.11.57","status":"affected"},{"version":">= 3.4.2, < 3.7.13","status":"affected"}]}],"references":[{"url":"https://github.com/traefik/traefik/security/advisories/GHSA-w4v4-9rw7-5326","name":"https://github.com/traefik/traefik/security/advisories/GHSA-w4v4-9rw7-5326","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/traefik/traefik/pull/13797","name":"https://github.com/traefik/traefik/pull/13797","tags":["x_refsource_MISC"]},{"url":"https://github.com/traefik/traefik/commit/a277e94664ffc1ce9543df552d3bbf48d4d3b8b3","name":"https://github.com/traefik/traefik/commit/a277e94664ffc1ce9543df552d3bbf48d4d3b8b3","tags":["x_refsource_MISC"]},{"url":"https://github.com/traefik/traefik/releases/tag/v2.11.57","name":"https://github.com/traefik/traefik/releases/tag/v2.11.57","tags":["x_refsource_MISC"]},{"url":"https://github.com/traefik/traefik/releases/tag/v3.7.13","name":"https://github.com/traefik/traefik/releases/tag/v3.7.13","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV4_0":{"attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"NONE","subConfidentialityImpact":"HIGH","subIntegrityImpact":"HIGH","subAvailabilityImpact":"NONE","baseScore":7,"baseSeverity":"HIGH","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N","version":"4.0"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-444","lang":"en","description":"CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-863","lang":"en","description":"CWE-863: Incorrect Authorization","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-09-10T14:57:06.162Z"},"source":{"advisory":"GHSA-w4v4-9rw7-5326","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-10T16:54:44.054899Z","id":"CVE-2026-88008","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-10T16:56:53.731Z"}}]}}}