{"id":"CVE-2026-65600","title":"Traefik versions <= v2.11.51, >= v3.6.0 <= v3.6.22, and >= v3.7.0 <= v3.7.6 contain an authentication bypass via path traversal in the ReplacePathRegex middleware","summary":"Traefik versions <= v2.11.51, >= v3.6.0 <= v3.6.22, and >= v3.7.0 <= v3.7.6 contain an authentication bypass via path traversal in the ReplacePathRegex middleware. When ReplacePathRegex is configured with a regex that captures user-contr…","severity":"medium","cvss":5.3,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","cwe":["CWE-22"],"vendor":"traefik","product":"traefik","affected":["traefik < 2.11.52","traefik >= 3.6.0, < 3.6.23","traefik >= 3.7.0, < 3.7.7"],"patched":["traefik 3.7.7"],"published":"2026-07-22","updated":"2026-10-08","sourceUpdated":"2026-10-08T16:17:28.820","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-65600","references":[{"url":"https://github.com/traefik/traefik/security/advisories/GHSA-cxjq-mrr5-89rv","label":"disclosure@vulncheck.com"},{"url":"https://www.vulncheck.com/advisories/traefik-before-authentication-bypass-via-replacepathregex","label":"disclosure@vulncheck.com"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-65600"},{"url":"https://github.com/traefik/traefik/commit/3f10dd442479530560f010167cac2947676d9b29"},{"url":"https://github.com/traefik/traefik/releases/tag/v2.11.52"},{"url":"https://github.com/traefik/traefik/releases/tag/v3.6.23"},{"url":"https://github.com/traefik/traefik/releases/tag/v3.7.7"},{"url":"https://github.com/advisories/GHSA-cxjq-mrr5-89rv"}],"tags":["nvd","cve.org","ghsa","go","score-dispute"],"ssvc":{"exploitation":"none","automatable":"yes","technicalImpact":"partial","timestamp":"2026-07-23T19:08:10.643487Z"},"scores":{"nvd":5.3,"cna":7.8,"ghsa":9.1},"epss":0.00621,"epssPercentile":0.49569,"aliases":["GHSA-cxjq-mrr5-89rv"],"ecosystem":"go","ingestedAt":"2026-08-06T17:00:12.691Z","slug":"CVE-2026-65600","body":"## Overview\n\nTraefik versions <= v2.11.51, >= v3.6.0 <= v3.6.22, and >= v3.7.0 <= v3.7.6 contain an authentication bypass via path traversal in the ReplacePathRegex middleware. When ReplacePathRegex is configured with a regex that captures user-controlled path segments without a mandatory path separator (e.g. regex \"^/api(.*)\", replacement \"/$1\"), the middleware forwards the replaced path to the backend without validating that it matches its normalized form. An unauthenticated remote attacker can send a crafted request (e.g. GET /api../admin) that produces an un-normalized path such as /../admin, which a backend that normalizes paths resolves to a protected route, bypassing authentication middleware. Fixed in v2.11.52, v3.6.23, and v3.7.7.\n\n## Affected\n\n- `traefik < 2.11.52`\n- `traefik >= 3.6.0, < 3.6.23`\n- `traefik >= 3.7.0, < 3.7.7`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `traefik 3.7.7`\n\n## Package advisory (CVE-2026-65600)\n\nAffected packages:\n\n- `github.com/traefik/traefik/v2 <= 2.11.51`\n- `github.com/traefik/traefik/v3 <= 3.6.22`\n- `github.com/traefik/traefik/v3 >= 3.7.0, <= 3.7.6`\n- `github.com/traefik/traefik <= 1.7.34`\n\nPatched in:\n\n- `github.com/traefik/traefik/v2 2.11.52`\n- `github.com/traefik/traefik/v3 3.6.23`\n- `github.com/traefik/traefik/v3 3.7.7`\n\nSource: https://github.com/advisories/GHSA-cxjq-mrr5-89rv","depth":"sunlit","depthScore":29,"depthScoreParts":{"impact":29.2,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[{"seq":218133,"id":"CVE-2026-65600","ts":1791478425589,"field":"cvss","old":"9.1","new":"5.3"},{"seq":218132,"id":"CVE-2026-65600","ts":1791478425589,"field":"severity","old":"critical","new":"medium"}]}