What’s Vulnerable › Vulnerabilities

CVE-2026-35051: Traefik: ForwardAuth trustForwardHeader=false allows spoofed X-Forwarded-Prefix to bypass auth

• Severity: critical (CVSS 10.0 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-04-30 · updated 2026-07-15
• Weakness: CWE-345

Description

Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.43, 3.6.14, and 3.7.0-rc.2, there is an authentication bypass vulnerability in Traefik's ForwardAuth middleware when trustForwardHeader=false is configured and Traefik is deployed behind a trusted upstream proxy. This issue has been patched in versions 2.11.43, 3.6.14, and 3.7.0-rc.2.

Affected products

• Traefik: before 2.11.43; from 3.0.0 before 3.6.14; 3.7.0-ea1, 3.7.0-ea2, 3.7.0-ea3, 3.7.0-rc1 — fixed in 2.11.43, 3.6.14

How to fix

Upgrade to a fixed version: Traefik 2.11.43, 3.6.14. Check the vendor advisory for mitigations.

References

• https://github.com/traefik/traefik/releases/tag/v2.11.43
• https://github.com/traefik/traefik/releases/tag/v3.6.14
• https://github.com/traefik/traefik/releases/tag/v3.7.0-rc.2
• https://github.com/traefik/traefik/security/advisories/GHSA-6384-m2mw-rf54
• https://access.redhat.com/errata/RHSA-2026:21772
• https://access.redhat.com/security/cve/CVE-2026-35051
• https://bugzilla.redhat.com/show_bug.cgi?id=2464235
• https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-35051.json

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