{"id":"CVE-2026-71326","aliases":["GHSA-6765-c87h-8mrf","GO-2026-6204"],"url":"https://o3.security/vulnerability/CVE-2026-71326","summary":"Traefik: BasicAuth singleflight key collision allows authenticated identity spoofing","details":"Traefik is an open source HTTP reverse proxy and load balancer. From 3.6.11 until 3.6.25 and 3.7.10, Traefik's BasicAuth middleware in pkg/middlewares/auth/basic_auth.go deduplicates concurrent password checks with a singleflight key built from the delimiter-free concatenation of password and secret, allowing an attacker who has a valid credential and the stored hash to authenticate as an unconfigured username when headerField trusts the forwarded identity. This issue is fixed in 3.6.25 and 3.7.10.","published":"2026-08-06T16:34:23.931Z","modified":"2026-09-18T03:48:29.422134282Z","cvss":null,"epss":{"score":0.00356,"percentile":0.29168,"asOf":"2026-09-16"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"github.com/traefik/traefik/v3","fixedVersion":"3.6.25"},{"ecosystem":"Go","name":"github.com/traefik/traefik/v3","fixedVersion":"3.7.10"}],"fix":{"url":"https://github.com/traefik/traefik/commit/b5ace8eb5d6779980567f5e75efd2d9e08b7e350","label":"traefik/traefik@b5ace8e"},"references":[{"type":"WEB","url":"https://github.com/traefik/traefik/releases/tag/v3.6.25"},{"type":"WEB","url":"https://github.com/traefik/traefik/releases/tag/v3.7.10"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/71xxx/CVE-2026-71326.json"},{"type":"ADVISORY","url":"https://github.com/traefik/traefik/security/advisories/GHSA-6765-c87h-8mrf"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-71326"},{"type":"FIX","url":"https://github.com/traefik/traefik/commit/b5ace8eb5d6779980567f5e75efd2d9e08b7e350"},{"type":"FIX","url":"https://github.com/traefik/traefik/pull/13572"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-18T03:48:29.422134282Z"}}