Traefik up to 2.11.54 TLS Option Resolution certificate validation

Summaryinfo

A vulnerability was found in Traefik up to 2.11.54. It has been classified as problematic. The affected element is an unknown function of the component TLS Option Resolution. This manipulation causes certificate validation. This vulnerability is tracked as CVE-2026-85597. The attack is possible to be carried out remotely. No exploit exists.

Detailsinfo

A vulnerability has been found in Traefik up to 2.11.54 and classified as problematic. Affected by this vulnerability is an unknown code block of the component TLS Option Resolution. The manipulation with an unknown input leads to a certificate validation vulnerability. The CWE definition for the vulnerability is CWE-295. The product does not validate, or incorrectly validates, a certificate. As an impact it is known to affect integrity. The summary by CVE is:

Traefik before v2.11.55 contains 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.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-85597 since 09/04/2026. The exploitation appears to be difficult. The attack can be launched remotely. The exploitation doesn't need any form of authentication. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1587.003 according to MITRE ATT&CK.

Upgrading to version 2.11.55 eliminates this vulnerability.

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Productinfo

Name

• Traefik

Version

• 2.11.0
• 2.11.1
• 2.11.2
• 2.11.3
• 2.11.4
• 2.11.5
• 2.11.6
• 2.11.7
• 2.11.8
• 2.11.9
• 2.11.10
• 2.11.11
• 2.11.12
• 2.11.13
• 2.11.14
• 2.11.15
• 2.11.16
• 2.11.17
• 2.11.18
• 2.11.19
• 2.11.20
• 2.11.21
• 2.11.22
• 2.11.23
• 2.11.24
• 2.11.25
• 2.11.26
• 2.11.27
• 2.11.28
• 2.11.29
• 2.11.30
• 2.11.31
• 2.11.32
• 2.11.33
• 2.11.34
• 2.11.35
• 2.11.36
• 2.11.37
• 2.11.38
• 2.11.39
• 2.11.40
• 2.11.41
• 2.11.42
• 2.11.43
• 2.11.44
• 2.11.45
• 2.11.46
• 2.11.47
• 2.11.48
• 2.11.49
• 2.11.50
• 2.11.51
• 2.11.52
• 2.11.53
• 2.11.54

Website

• Product: https://github.com/traefik/traefik/

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