{"affected":[{"defaultStatus":"unaffected","ecosystem":"golang","packageName":"github.com/traefik/traefik/v2","product":"traefik","source":"CNA: VulnCheck","vendor":"traefik","versions":[{"lessThan":"2.11.60","status":"affected","version":"0","versionType":"semver"},{"status":"unaffected","version":"2.11.60","versionType":"semver"}]},{"defaultStatus":"unaffected","ecosystem":"golang","packageName":"github.com/traefik/traefik/v3","product":"traefik","source":"CNA: VulnCheck","vendor":"traefik","versions":[{"lessThan":"3.7.16","status":"affected","version":"3.0.0","versionType":"semver"},{"status":"unaffected","version":"3.7.16","versionType":"semver"}]}],"cveId":"CVE-2026-121966","cwes":["CWE-488"],"description":"Traefik 2.x before 2.11.60 and 3.x before 3.7.16 sends ForwardAuth subrequests (and, in 3.7, Ingress NGINX auth-url requests) through an auth-server connection pool shared by all clients, exposing connection-bound NTLM or Negotiate authentication. An unauthenticated attacker can reuse another user's authenticated connection, receiving the victim's identity via authResponseHeaders to access backends as that user.","epss":null,"exploits":[],"kev":null,"metrics":[{"score":7,"severity":"high","source":"CNA: VulnCheck","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N","version":"4.0"},{"score":8.7,"severity":"high","source":"CNA: VulnCheck","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N","version":"3.1"},{"score":7,"severity":"high","source":"NVD: disclosure@vulncheck.com","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","version":"4.0"},{"score":8.7,"severity":"high","source":"NVD: disclosure@vulncheck.com","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N","version":"3.1"}],"modifiedAt":1793809070303,"publishedAt":1793806408106,"references":[{"source":"CNA: VulnCheck","tags":["vendor-advisory"],"url":"https://github.com/traefik/traefik/security/advisories/GHSA-hrpp-p4fc-wwf8"},{"source":"CNA: VulnCheck","tags":["third-party-advisory"],"url":"https://www.vulncheck.com/advisories/traefik-before-2.11.60-and-3.7.16-forwardauth-ntlm-negotiate-identity-leak"},{"source":"disclosure@vulncheck.com","tags":[],"url":"https://github.com/traefik/traefik/security/advisories/GHSA-hrpp-p4fc-wwf8"},{"source":"disclosure@vulncheck.com","tags":[],"url":"https://www.vulncheck.com/advisories/traefik-before-2.11.60-and-3.7.16-forwardauth-ntlm-negotiate-identity-leak"}],"remediation":[],"revision":"0c805d81038240cde71603c7c94899810ecb6ff191499c7a9ae24c62e5cfff21","sources":[{"modifiedAt":1793806408106,"name":"CNA: VulnCheck","retrievedAt":1793808644090,"url":"https://www.cve.org/CVERecord?id=CVE-2026-121966"},{"modifiedAt":1793809070303,"name":"NVD","retrievedAt":1793816718080,"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-121966"}],"ssvc":null,"status":"published","title":"Traefik before 2.11.60 and 3.7.16 ForwardAuth NTLM/Negotiate Identity Leak","updatedAt":1793816718080}