{"id":"CVE-2026-114640","kind":"vulnerability","aliases":["CVE-2026-114640"],"related":[],"title":"Traefik: forged client certificate headers bypass mTLS authentication on HTTP","description":"Traefik from v3.7.0 before v3.7.14 contains an authentication bypass vulnerability in its Kubernetes Ingress-NGINX provider that forwards client-supplied Ssl-Client-* headers on the plaintext HTTP router. When ssl-redirect is disabled alongside auth-tls-pass-certificate-to-upstream, unauthenticated attackers can send Ssl-Client-Verify: SUCCESS with a chosen certificate subject and issuer to impersonate mTLS identities.","summary":"Traefik's Kubernetes Ingress-NGINX provider trusts client-supplied Ssl-Client-* headers on its plaintext HTTP router. An unauthenticated attacker can send Ssl-Client-Verify: SUCCESS with a chosen subject and issuer to impersonate any mTLS identity.","severity":"high","cvss":8.7,"epss":0.00202,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["ingress-nginx","kubernetes","runtime","traefik"],"not_affected_if":["default-config","traefik-3.7.14-or-later","traefik-below-3.7.0"],"how_to_check":"Check the Traefik version is 3.7.0 or later; the flaw is in v3.7.0 before v3.7.14.\nCheck whether ingress annotations set nginx.ingress.kubernetes.io/ssl-redirect to false together with nginx.ingress.kubernetes.io/auth-tls-pass-certificate-to-upstream to true.","fix":"Upgrade Traefik to v3.7.14 or later.\nUntil upgraded, remove ssl-redirect disabling or auth-tls-pass-certificate-to-upstream from affected ingresses.","status":"open","published_at":"2026-10-22T02:16:56+00:00","first_seen_at":"2026-10-23T21:57:30+00:00","triaged_at":"2026-10-23T22:35:28+00:00","updated_at":"2026-10-24T07:15:52+00:00","category":"runtime","confidence":0.7,"triage":{"at":"2026-10-23T22:35:28Z","model":"claude-haiku-5-5","output":{"fix":"Upgrade Traefik to v3.7.14 or later.\nUntil upgraded, remove ssl-redirect disabling or auth-tls-pass-certificate-to-upstream from affected ingresses.","reach":"internet","title":"Traefik: forged client certificate headers bypass mTLS authentication on HTTP","impact":"high","summary":"Traefik's Kubernetes Ingress-NGINX provider trusts client-supplied Ssl-Client-* headers on its plaintext HTTP router. An unauthenticated attacker can send Ssl-Client-Verify: SUCCESS with a chosen subject and issuer to impersonate any mTLS identity.","category":"runtime","who_cares":["traefik","kubernetes","ingress-nginx"],"confidence":0.7,"needs_auth":"no","worst_case":"attacker impersonates an mTLS identity and reaches protected upstream services","analyst_note":"","how_to_check":"Check the Traefik version is 3.7.0 or later; the flaw is in v3.7.0 before v3.7.14.\nCheck whether ingress annotations set nginx.ingress.kubernetes.io/ssl-redirect to false together with nginx.ingress.kubernetes.io/auth-tls-pass-certificate-to-upstream to true.\nunknown for any further exact check the sources do not give.","needs_analyst":false,"not_affected_if":["default-config","traefik-below-3.7.0","traefik-3.7.14-or-later"],"user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"high"},"cost_usd":0.000576,"input_tokens":2999,"output_tokens":552,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-114640':13A,16A '-2026':12A,15A 'alongsid':101C 'attack':45B,110C 'auth':103C 'auth-tls-pass-certificate-to-upstream':102C 'authent':8A,71C 'bypass':6A,72C 'certif':4A,106C,121C 'chosen':55B,120C 'client':3A,32B,36B,50B,84C,88C,115C 'client-suppli':31B,83C 'contain':69C 'cve':11A,14A 'disabl':100C 'forg':2A 'forward':82C 'header':5A,37B,89C 'http':10A,41B,93C 'ident':63B,128C 'imperson':60B,126C 'ingress':18B,27B,78C 'ingress-nginx':17B,26B,77C 'issuer':58B,124C 'kubernet':20B,25B,76C 'mtls':7A,62B,127C 'nginx':19B,28B,79C 'pass':105C 'plaintext':40B,92C 'provid':29B,80C 'redirect':98C 'router':42B,94C 'runtim':21B 'send':47B,112C 'ssl':35B,49B,87C,97C,114C 'ssl-client':34B,86C 'ssl-client-verifi':48B,113C 'ssl-redirect':96C 'subject':56B,122C 'success':52B,117C 'suppli':33B,85C 'tls':104C 'traefik':1A,22B,23B,64C 'trust':30B 'unauthent':44B,109C 'upstream':108C 'v3.7.0':66C 'v3.7.14':68C 'verifi':51B,116C 'vulner':73C","nicknames":[],"mitigations":[],"who_affected":null,"tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-22T02:16:56+00:00","kev":null,"cvss_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","cvss_by":"disclosure@vulncheck.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-114640","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-114640","severity":null,"published_at":"2026-10-22T02:16:56+00:00","modified_at":"2026-10-22T15:39:30+00:00","first_seen_at":"2026-10-23T21:57:30+00:00","fetched_at":"2026-10-23T22:29:02+00:00","note":null},{"source":"epss","external_id":"CVE-2026-114640","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-114640","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-24T07:15:52+00:00","fetched_at":"2026-10-25T12:38:51+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}