7.8High

CVE-2026-32305Traefik mTLS bypass via fragmented ClientHello SNI extraction failure

traefik traefik; Red Hat Red Hat OpenShift Dev Spaces 3.27; Red Hat Red Hat OpenShift Dev Spaces 3.28; Red Hat Red Hat OpenShift GitOps Published: (8 months ago)

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.

Weakness (CWE): CWE-287CWE-1188CWE-179

Data: CVE.org, NVD, CISA KEV, FIRST EPSS, Ubuntu. Published as the sources state it, in English.

Affected products and versions

VendorProductVersions
openshift devspaces 3.27 —
openshift devspaces 3.28 —
Red Hat Red Hat OpenShift Dev Spaces 3.27 all versions
Red Hat Red Hat OpenShift Dev Spaces 3.28 all versions
Red Hat Red Hat OpenShift GitOps all versions
traefik traefik < 2.11.41, >= 3.0.0-beta1, < 3.6.11, >= 3.7.0-ea.1, < 3.7.0-ea.2

References and patches

CPE matches (NVD) (3)

  • cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:* < 2.11.41
  • cpe:2.3:a:traefik:traefik:*:*:*:*:*:*:*:* ≥ 3.0.0 ≤ 3.6.11
  • cpe:2.3:a:traefik:traefik:3.7.0:ea1:*:*:*:*:*:*