SB2026102198 - Improper Authentication in Traefik

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Main Vulnerability Database SB2026102198

SB2026102198 - Improper Authentication in Traefik

Published: October 21, 2026

Security Bulletin ID SB2026102198
CSH Severity
High
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

High 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Improper Authentication (CVE-ID: N/A)

CWE-ID: CWE-287 - Improper Authentication

CVSSv4: 9.1 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to bypass authentication and access a backend using another client's identity.

The vulnerability exists due to improper authentication isolation in Traefik's ForwardAuth middleware and Kubernetes Ingress NGINX external authentication handling when authentication subrequests use a shared connection pool with connection-bound authentication such as NTLM or SPNEGO/Kerberos Negotiate. A remote attacker can send a request over a separate frontend connection that reuses an authentication-server connection already authenticated by another client to obtain a successful authentication response carrying that client's identity and access the backend as that user.


Remediation

Install update from vendor's website.

References