CVE-2026-114642: traefik Cert Validation Flaw — Fix

Description

Traefik 2.11.0 before 2.11.58 and 3.0.0 before 3.7.14 stores its NTLM/Kerberos backend round tripper in a client-connection slot not keyed by ServersTransport, so one service's TLS client configuration is reused for another service's backend. An unauthenticated client can arm the slot via a backend issuing an NTLM or Negotiate challenge, then reach another service on the same keep-alive connection, bypassing its root CAs, server name, and certificate verification.

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CVSS v3.1 Score

8.7

HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N

EPSS — Exploit Prediction

0.0019

Probability of exploitation

0.09%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-295 CWE-295

Affected Products

Vendor	Product	Versions
traefik	traefik	2.11.0 — 2.11.58
traefik	traefik	3.0.0 — 3.7.14

References

Advisories & Patches

https://github.com/traefik/traefik/security/advisories/GHSA-cw35-4q88-3rmp

Other References

https://www.vulncheck.com/advisories/traefik-before-2.11.58-and-3.7.14-tls-config-bypass-via-ntlm-kerberos-round-tripper

Frequently Asked Questions

What is CVE-2026-114642? +

Traefik 2.11.0 before 2.11.58 and 3.0.0 before 3.7.14 stores its NTLM/Kerberos backend round tripper in a client-connection slot not keyed by ServersTransport, so one service's TLS client configuration is reused for another service's backend. An unauthenticated client can arm the slot via a backend issuing an NTLM or Negotiate challenge, then reach another service on the same keep-alive connection, bypassing its root CAs, server name, and certificate verification. It has a CVSS v3.1 base score of 8.7 (HIGH).

How severe is CVE-2026-114642? +

CVE-2026-114642 has a CVSS v3.1 score of 8.7 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0019, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-114642? +

CVE-2026-114642 affects products from traefik, specifically: traefik. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-114642? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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