{"id":"CVE-2025-66491","summary":"Traefik has Inverted TLS Verification Logic in its ingress-nginx Provider","details":"Traefik is an HTTP reverse proxy and load balancer. Versions 3.5.0 through 3.6.2 have inverted TLS verification logic in the nginx.ingress.kubernetes.io/proxy-ssl-verify annotation. Setting the annotation to \"on\" (intending to enable backend TLS certificate verification) actually disables verification, allowing man-in-the-middle attacks against HTTPS backends when operators believe they are protected. This issue is fixed in version 3.6.3.","aliases":["GHSA-7vww-mvcr-x6vj","GO-2025-4205"],"modified":"2026-04-10T04:16:23.177121Z","published":"2025-12-09T00:38:39.208Z","related":["SUSE-SU-2026:0037-1","openSUSE-SU-2026:10020-1"],"database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-295"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/66xxx/CVE-2025-66491.json"},"references":[{"type":"WEB","url":"https://github.com/traefik/traefik/releases/tag/v3.6.3"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/66xxx/CVE-2025-66491.json"},{"type":"ADVISORY","url":"https://github.com/traefik/traefik/security/advisories/GHSA-7vww-mvcr-x6vj"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-66491"},{"type":"FIX","url":"https://github.com/traefik/traefik/commit/14a1aedf5704673d875d210d7bacf103a43c77e4"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/traefik/traefik","events":[{"introduced":"2cbd96e64c929bea8f933efa75080e9656314f34"},{"fixed":"f6ea1f473a8468c119739cbda5c4fd3f1f886ec2"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-66491.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N"}]}