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.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact High

Subsequent System Integrity Impact High

Subsequent System Availability Impact None

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
traefik traefik affected
Version Status Constraints
< 2.11.41 affected —
>= 3.0.0-beta1, < 3.6.11 affected —
>= 3.7.0-ea.1, < 3.7.0-ea.2 affected —

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Project Subscriptions

No data.

Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/traefik/traefik/releases/tag/v2.11.41 cve-icon cve-icon
https://github.com/traefik/traefik/releases/tag/v3.6.11 cve-icon cve-icon
https://github.com/traefik/traefik/releases/tag/v3.7.0-ea.2 cve-icon cve-icon
https://github.com/traefik/traefik/security/advisories/GHSA-wvvq-wgcr-9q48 cve-icon cve-icon
History

Fri, 20 Mar 2026 10:30:00 +0000

Type Values Removed Values Added
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.
Title Traefik mTLS bypass via fragmented ClientHello SNI extraction failure
Weaknesses CWE-1188
CWE-287
References
Metrics cvssV4_0

{'score': 7.8, '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'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-03-20T10:01:13.620Z

Reserved: 2026-03-11T21:16:21.659Z

Link: CVE-2026-32305

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-03-20T11:18:02.360

Modified: 2026-03-20T11:18:02.360

Link: CVE-2026-32305

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses