CVEvulnerability

CVE-2026-32305

7.8 HIGH Published 2026-03-20 Modified 2026-07-15 Official page ↗
Status
Modified
Published
2026-03-20
Last modified
2026-07-15
Assigner
[email protected]
CVSS 4.0 ([email protected])
7.8 HIGH — CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/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:X/V:X/RE:X/U:X
CVSS 3.1 ([email protected])
5.3 MEDIUM — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
CVSS 3.1 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c)
8.3 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L
Weaknesses
CWE-1188, CWE-179, CWE-287

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.

Affected configurations

• traefik traefik (< 2.11.41) • traefik traefik (>= 3.0.0 <= 3.6.11) • traefik traefik 3.7.0

Related

Weakness · CWE (3)

  • CWE-1188 Initialization of a Resource with an Insecure Default weakness
  • CWE-179 Incorrect Behavior Order: Early Validation weakness
  • CWE-287 Improper Authentication weakness

References