{"cve":"CVE-2026-71326","nvd":{"published":"2026-08-06T22:18:29.650","modified":"2026-09-16T20:44:44.453","status":"Analyzed","description":"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.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N","score":2.1},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N","score":3.8},"cwes":["CWE-287"],"references":["https://github.com/traefik/traefik/commit/b5ace8eb5d6779980567f5e75efd2d9e08b7e350","https://github.com/traefik/traefik/pull/13572","https://github.com/traefik/traefik/releases/tag/v3.6.25","https://github.com/traefik/traefik/releases/tag/v3.7.10","https://github.com/traefik/traefik/security/advisories/GHSA-6765-c87h-8mrf"],"products":["traefik:traefik"],"source":"nvd","synced_at":"2026-10-19T22:47:54.990491175+00:00"},"epss":{"cve":"CVE-2026-71326","score":0.00337,"percentile":0.27078,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-6765-c87h-8mrf","url":"https://osv.dev/vulnerability/GHSA-6765-c87h-8mrf","summary":"Traefik: BasicAuth singleflight key collision allows authenticated identity spoofing","modified":"2026-08-18T15:10:47.240700768Z","packages":[{"ecosystem":"Go","name":"github.com/traefik/traefik/v3","purl":"pkg:golang/github.com/traefik/traefik/v3","ranges":[">=3.6.11 <3.6.25"],"fixed":["3.6.25"]},{"ecosystem":"Go","name":"github.com/traefik/traefik/v3","purl":"pkg:golang/github.com/traefik/traefik/v3","ranges":[">=3.7.0 <3.7.10"],"fixed":["3.7.10"]}]},{"id":"GO-2026-6204","url":"https://osv.dev/vulnerability/GO-2026-6204","summary":"Traefik: BasicAuth singleflight key collision allows authenticated identity spoofing in github.com/traefik/traefik","modified":"2026-08-18T15:00:14.365618504Z","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":["all versions"],"fixed":[]},{"ecosystem":"Go","name":"github.com/traefik/traefik/v3","purl":"pkg:golang/github.com/traefik/traefik/v3","ranges":[">=3.6.11 <3.6.25",">=3.7.0 <3.7.10"],"fixed":["3.6.25","3.7.10"]}]}],"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."]}