CVE-2026-85597

CriticalCVSS 9.1/10Last modified Oct 8, 2026

Description

Traefik before v2.11.55 and v3.0.0 through v3.7.10 contain a TLS option conflict resolution vulnerability that allows unauthenticated attackers to bypass client-certificate authentication by creating conflicting TLS options on multi-host routers. Attackers can reach protected backends by exploiting shared TLS resolution across multiple hostnames in a single router rule, causing the strict mTLS requirement to fall back to default options for all hosts.

Metrics

CVSS 3.1 9.1/10CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Weakness enumeration

CWE-863

Affected software

Vendor	Product	Versions
traefik	traefik	< 2.11.55
traefik	traefik	>= 3.0.0, <= 3.7.10

References

https://github.com/traefik/traefik/security/advisories/GHSA-g55h-rg46-x9c5Exploit, Mitigation, Patch, Vendor Advisory
https://www.vulncheck.com/advisories/traefik-before-2.11.55-mtls-bypass-via-tls-option-conflictThird Party Advisory

Timeline

Published: Sep 4, 2026
Last modified: Oct 8, 2026
NVD status: Analyzed

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