Vulnerability Description
Traefik is an HTTP reverse proxy and load balancer. Versions 2.11.40 and below, 3.0.0-beta1 through 3.6.11, and 3.7.0-ea.1 are vulnerable to mTLS bypass through the TLS SNI pre-sniffing logic related to fragmented ClientHello packets. When a TLS ClientHello is fragmented across multiple records, Traefik's SNI extraction may fail with an EOF and return an empty SNI. The TCP router then falls back to the default TLS configuration, which does not require client certificates by default. This allows an attacker to bypass route-level mTLS enforcement and access services that should require mutual TLS authentication. This issue is patched in versions 2.11.41, 3.6.11 and 3.7.0-ea.2.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Traefik | Traefik | < 2.11.41 |
Related Weaknesses (CWE)
References
- https://github.com/traefik/traefik/releases/tag/v2.11.41Release Notes
- https://github.com/traefik/traefik/releases/tag/v3.6.11Release Notes
- https://github.com/traefik/traefik/releases/tag/v3.7.0-ea.2Release Notes
- https://github.com/traefik/traefik/security/advisories/GHSA-wvvq-wgcr-9q48PatchVendor Advisory
FAQ
What is CVE-2026-32305?
CVE-2026-32305 is a vulnerability with a CVSS score of 5.3 (MEDIUM). Traefik is an HTTP reverse proxy and load balancer. Versions 2.11.40 and below, 3.0.0-beta1 through 3.6.11, and 3.7.0-ea.1 are vulnerable to mTLS bypass through the TLS SNI pre-sniffing logic related ...
How severe is CVE-2026-32305?
CVE-2026-32305 has been rated MEDIUM with a CVSS base score of 5.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-32305?
Check the references section above for vendor advisories and patch information. Affected products include: Traefik Traefik.