{"cve":"CVE-2026-71324","nvd":{"published":"2026-08-06T22:18:29.310","modified":"2026-09-16T20:46:12.443","status":"Analyzed","description":"Traefik is an open source HTTP reverse proxy and load balancer. Prior to 2.11.53, 3.6.24, and 3.7.9, Traefik's default HTTP reverse proxy forwards a plain HTTP/2 or HTTP/3 CONNECT request and its body to an HTTP/1.1 upstream through a shared net/http.Transport. When the upstream answers the CONNECT with a keep-alive non-2xx response and does not drain the body, Traefik returns the desynchronized backend socket to its shared pool and reuses it for other clients. An unauthenticated attacker can use this behavior to make a different client read the attacker's smuggled response, which can include authenticated or private content from another request. The ForwardAuth middleware with forwardBody true and preserveRequestMethod true can re-issue a CONNECT with the buffered body attached, exposing the auth-client pool to the same desynchronization. This issue is fixed in 2.11.53, 3.6.24, and 3.7.9.","cvss_v4":{"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","score":7.0},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","score":9.1},"cwes":["CWE-444"],"references":["https://github.com/traefik/traefik/commit/04d36f28e4eae7535e96a6351dd9f7bfb48a30e7","https://github.com/traefik/traefik/commit/0807b6d5dd1da8b2f7f4076ea2392b5437bf2ab0","https://github.com/traefik/traefik/commit/94a7508817d180f0ab2f1eae93df48d4ab19ecce","https://github.com/traefik/traefik/pull/13542","https://github.com/traefik/traefik/pull/13543"],"products":["traefik:traefik"],"source":"nvd","synced_at":"2026-10-19T22:47:54.990491175+00:00"},"epss":{"cve":"CVE-2026-71324","score":0.01063,"percentile":0.64658,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-3ccp-42pg-hgv6","url":"https://osv.dev/vulnerability/GHSA-3ccp-42pg-hgv6","summary":"Traefik: Cross-user response poisoning via proxied CONNECT on Traefik's shared backend keep-alive pool","modified":"2026-08-18T15:10:47.771430180Z","packages":[{"ecosystem":"Go","name":"github.com/traefik/traefik/v2","purl":"pkg:golang/github.com/traefik/traefik/v2","ranges":["<2.11.53"],"fixed":["2.11.53"]},{"ecosystem":"Go","name":"github.com/traefik/traefik/v3","purl":"pkg:golang/github.com/traefik/traefik/v3","ranges":["<3.6.24"],"fixed":["3.6.24"]},{"ecosystem":"Go","name":"github.com/traefik/traefik/v3","purl":"pkg:golang/github.com/traefik/traefik/v3","ranges":[">=3.7.0 <3.7.9"],"fixed":["3.7.9"]},{"ecosystem":"Go","name":"github.com/traefik/traefik","purl":"pkg:golang/github.com/traefik/traefik","ranges":["<=1.7.34"],"fixed":[]}]},{"id":"GO-2026-6201","url":"https://osv.dev/vulnerability/GO-2026-6201","summary":"Traefik: Cross-user response poisoning via proxied CONNECT on Traefik's shared backend keep-alive pool in github.com/traefik/traefik","modified":"2026-08-18T15:00:19.804323790Z","packages":[{"ecosystem":"Go","name":"github.com/traefik/traefik","purl":"pkg:golang/github.com/traefik/traefik","ranges":["all versions"],"fixed":[]},{"ecosystem":"Go","name":"github.com/traefik/traefik/v2","purl":"pkg:golang/github.com/traefik/traefik/v2","ranges":["<2.11.53"],"fixed":["2.11.53"]},{"ecosystem":"Go","name":"github.com/traefik/traefik/v3","purl":"pkg:golang/github.com/traefik/traefik/v3","ranges":["<3.6.24",">=3.7.0 <3.7.9"],"fixed":["3.6.24","3.7.9"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}