CVE-2026-85596: Critical severity (CVSS 9.8)

Description

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.

CVSS 3.1 breakdown

Attack vectorNetwork

Attack complexityLow

Privileges requiredNone

User interactionNone

ScopeUnchanged

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Traefik Traefik≥ 3.7.0 < 3.7.11

Remediation

Fixed in

Traefik Traefik≥ 3.7.11

Patch & vendor advisories

https://github.com/traefik/traefik/security/advisories/GHSA-j994-9gqj-9hwq

References

https://github.com/traefik/traefik/security/advisories/GHSA-j994-9gqj-9hwqExploitMitigationPatchVendor Advisory
https://www.vulncheck.com/advisories/traefik-3.7-authentication-bypass-via-tls-option-conflictThird Party Advisory

Related CVEs

Recent high-severity vulnerabilities sharing a weakness type.

Frequently asked

Is CVE-2026-85596 being actively exploited?

CVE-2026-85596 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.22%.

How severe is CVE-2026-85596?

CVE-2026-85596 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 0.22% probability of exploitation.

Which products are affected by CVE-2026-85596?

Affected products include Traefik Traefik.

How do I fix CVE-2026-85596?

Upgrade affected software to a fixed version, for example Traefik Traefik 3.7.11 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-85596 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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