{"cve":"CVE-2025-66490","nvd":{"published":"2025-12-09T01:16:55.540","modified":"2026-10-14T22:10:00.210","status":"Analyzed","description":"Traefik is an HTTP reverse proxy and load balancer. For versions prior to 2.11.32 and 2.11.31 through 3.6.2, requests using PathPrefix, Path or PathRegex matchers can bypass path normalization. When Traefik uses path-based routing, requests containing URL-encoded restricted characters (/, \\, Null, ;, ?, #) can bypass the middleware chain and reach unintended backends. For example, a request to http://mydomain.example.com/admin%2F could reach service-a without triggering my-security-middleware, bypassing security controls for the /admin/ path. This issue is fixed in versions 2.11.32 and 3.6.3.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","score":6.9},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N","score":6.5},"cwes":["CWE-436"],"references":["https://github.com/traefik/traefik/releases/tag/v2.11.32","https://github.com/traefik/traefik/releases/tag/v3.6.4","https://github.com/traefik/traefik/security/advisories/GHSA-gm3x-23wp-hc2c","https://github.com/traefik/traefik/security/advisories/GHSA-gm3x-23wp-hc2c"],"products":["traefik:traefik"],"source":"nvd","synced_at":"2026-10-19T22:16:40.427100871+00:00"},"epss":{"cve":"CVE-2025-66490","score":0.00439,"percentile":0.37897,"date":"2026-10-25"},"kev":null,"osv":[{"id":"GHSA-gm3x-23wp-hc2c","url":"https://osv.dev/vulnerability/GHSA-gm3x-23wp-hc2c","summary":"Path Normalization Bypass in Traefik Router + Middleware Rules","modified":"2026-04-16T02:14:32.835255100Z","packages":[{"ecosystem":"Go","name":"github.com/traefik/traefik","purl":"pkg:golang/github.com/traefik/traefik","ranges":["<=1.7.34"],"fixed":[]},{"ecosystem":"Go","name":"github.com/traefik/traefik/v2","purl":"pkg:golang/github.com/traefik/traefik/v2","ranges":["<2.11.32"],"fixed":["2.11.32"]},{"ecosystem":"Go","name":"github.com/traefik/traefik/v3","purl":"pkg:golang/github.com/traefik/traefik/v3","ranges":["<3.6.3"],"fixed":["3.6.3"]}]},{"id":"GO-2025-4206","url":"https://osv.dev/vulnerability/GO-2025-4206","summary":"Path Normalization Bypass in Traefik Router + Middleware Rules in github.com/traefik/traefik","modified":"2026-04-16T02:14:30.441751983Z","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":["<2.11.32"],"fixed":["2.11.32"]},{"ecosystem":"Go","name":"github.com/traefik/traefik/v3","purl":"pkg:golang/github.com/traefik/traefik/v3","ranges":["<3.6.3"],"fixed":["3.6.3"]}]}],"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."]}