Description
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.
Published: 2026-09-04
Score: 8.2 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Fri, 04 Sep 2026 19:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 04 Sep 2026 11:45:00 +0000

Type Values Removed Values Added
Description 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.
Title Traefik before v2.11.55 mTLS Bypass via TLS Option Conflict
First Time appeared Traefik
Traefik traefik
Weaknesses CWE-863
CPEs cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:*
Vendors & Products Traefik
Traefik traefik
References
Metrics cvssV4_0

{'score': 8.2, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-09-04T18:04:02.286Z

Reserved: 2026-09-04T11:00:28.730Z

Link: CVE-2026-85597

cve-icon Vulnrichment

Updated: 2026-09-04T18:03:59.136Z

cve-icon NVD

Status : Received

Published: 2026-09-04T12:17:23.210

Modified: 2026-09-04T18:18:03.927

Link: CVE-2026-85597

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-04T13:00:05Z

Weaknesses