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Review reviewHigh

CVE-2026-32305

traefik traefik, Red Hat OpenShift Dev Spaces 3.27, Red Hat OpenShift Dev Spaces 3.28

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...

CVSS
7.8
EPSS
0.40%
33.3% percentile
CISA KEV
Not listed
Published
2026.03.20
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.40%
Technical severityCVSS 7.8

Vulnerability overview

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...

Affected product and versions

Product
traefik traefik, Red Hat OpenShift Dev Spaces 3.27, Red Hat OpenShift Dev Spaces 3.28
Affected versions
>= < 2.11.41, >= >= 3.0.0-beta1, < 3.6.11, >= >= 3.7.0-ea.1, < 3.7.0-ea.2, < 2.11.41, >= 3.0.0 <= 3.6.11, 3.7.0
Fixed versions
2.11.41

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that traefik traefik, Red Hat OpenShift Dev Spaces 3.27, Red Hat OpenShift Dev Spaces 3.28 and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
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
CWE
CWE-1188, CWE-179, CWE-287
CVE-2026-32305 — traefik traefik, Red Hat OpenShift Dev Spaces 3.27, Red Hat OpenShift Dev Spaces 3.28 | SECUFOCUS NOW