CVE-2026-85597CWE-863broken-access-control

CVE-2026-85597

Critical · published September 4, 2026

CVSS v3.1
9.1
EPSS
0%
Percentile
27.6
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
9.1 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CVSS v4.0
8.2 · 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
EPSS
0.00351 · 27.6th percentile
Weakness
CWE-863 · Incorrect Authorization
Published
2026-09-04T16:17Z
Affected products (2)
ProductVersionsFixed in
traefik/traefik< 2.11.552.11.55
traefik/traefik≥ 3.0.0, < 3.7.113.7.11
References (2)
https://github.com/traefik/traefik/security/advisories/GHSA-g55h-rg46-x9c5 · [email protected]https://www.vulncheck.com/advisories/traefik-before-2.11.55-mtls-bypass-via-tls-option-conflict · [email protected]
EPSS history
Timeline
  • 06 SEP 03:33Z
    EPSS moved — → 0%
    epss
  • 04 SEP 11:30Z
    Traefik before v2.11.55 mTLS Bypass via TLS Option Conflict
    cvelistv5