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Vulnerability record · CVE-2026-85597 · published 4 September 2026

CVE-2026-85597: Traefik incorrect authorization vulnerability

Traefik · Traefik

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.

8.2 CVSS 4.0 High EPSS 0.35% · top 73.8% CWE-863 · Incorrect authorization
8.2CVSS 4.0 base score
0.35%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
2References, 1 tagged exploit
16 Sep 2026Last modified by NVD

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.

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/traefik/traefik/security/advisories/GHSA-g55h-rg46-x9c5 ExploitMitigationPatchVendor Advisory
https://www.vulncheck.com/advisories/traefik-before-2.11.55-mtls-bypass-via-tls-option-conflict Third Party Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-85597), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.