Auth bypass in Traefik
CVE-2026-85596
Traefik versions >= v3.7.0 and <= v3.7.10 contain an authentication bypass in the Kubernetes Ingress NGINX provider. The TLS option generated for an Ingress carrying the nginx.ingress.kubernetes.io/auth-tls-secret annotation was named after the Ingress namespace and name. As a result, two Ingress objects sharing the same host, the same client CA secret, and the same client-authentication mode produced two distinct TLS option names for that host. Traefik treats this as a TLS options conflict and falls back to the entry point's default TLS configuration, which does not request a client certificate, so a route configured with nginx.ingress.kubernetes.io/auth-tls-verify-client: "on" becomes reachable without a client certificate. Only the v3.7 line is affected; the issue is fixed in v3.7.11.
Vulnerability class: Broken Authentication
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.004 (36.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 36th percentile — 36.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.004 · change: +0.002
Affected products
Weakness classification (CWE)
References
- github.com/traefik/traefik/security/advisories/GHSA-j994-9gqj-9hwq (Exploit, vendor-advisory, Patch, Mitigation, Vendor Advisory)
- www.vulncheck.com/advisories/traefik-3.7-authentication-bypass-via-tls-option-c… (Third Party Advisory, third-party-advisory)
Frequently asked questions
- What is CVE-2026-85596?
- CVE-2026-85596 is a critical-severity vulnerability in Traefik, classified under Improper Authentication. CVSS score: 9.8/10. Published 2026-09-04.
- How severe is CVE-2026-85596?
- Critical severity. CVSS v3 base score is 9.8 out of 10.