{"id":"CVE-2026-71326","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 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 bui…","severity":"low","cvss":3.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N","cwe":["CWE-287","CWE-836"],"vendor":"traefik","product":"traefik","affected":["traefik >= 3.6.11, < 3.6.25","traefik >= 3.7.0, < 3.7.10"],"patched":["traefik 3.7.10"],"published":"2026-08-06","updated":"2026-09-16","sourceUpdated":"2026-09-16T20:44:44.453","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-71326","references":[{"url":"https://github.com/traefik/traefik/commit/b5ace8eb5d6779980567f5e75efd2d9e08b7e350","label":"security-advisories@github.com"},{"url":"https://github.com/traefik/traefik/pull/13572","label":"security-advisories@github.com"},{"url":"https://github.com/traefik/traefik/releases/tag/v3.6.25","label":"security-advisories@github.com"},{"url":"https://github.com/traefik/traefik/releases/tag/v3.7.10","label":"security-advisories@github.com"},{"url":"https://github.com/traefik/traefik/security/advisories/GHSA-6765-c87h-8mrf","label":"security-advisories@github.com"},{"url":"https://github.com/advisories/GHSA-6765-c87h-8mrf"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-71326.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-71326"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2512295"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-71326"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-71326"}],"tags":["nvd","ghsa","go","csaf","vex","red-hat"],"epss":0.00337,"epssPercentile":0.24362,"aliases":["GHSA-6765-c87h-8mrf"],"ecosystem":"go","ingestedAt":"2026-08-06T17:00:12.867Z","slug":"CVE-2026-71326","body":"## Overview\n\nTraefik 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.\n\n## Affected\n\n- `traefik >= 3.6.11, < 3.6.25`\n- `traefik >= 3.7.0, < 3.7.10`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `traefik 3.7.10`\n\n## Package advisory (CVE-2026-71326)\n\nAffected packages:\n\n- `github.com/traefik/traefik/v3 >= 3.6.11, <= 3.6.24`\n- `github.com/traefik/traefik/v3 >= 3.7.0, <= 3.7.9`\n\nPatched in:\n\n- `github.com/traefik/traefik/v3 3.6.25`\n- `github.com/traefik/traefik/v3 3.7.10`\n\nSource: https://github.com/advisories/GHSA-6765-c87h-8mrf\n\n## Vendor advisories\n\n- **Red Hat VEX** · Low · updated 2026-09-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-71326.json)","depth":"sunlit","depthScore":21,"depthScoreParts":{"impact":20.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":205758,"id":"CVE-2026-71326","ts":1789592771786,"field":"cvss","old":null,"new":"3.8"}]}