SB2026050534 - Authentication Bypass by Spoofing in Traefik

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Main Vulnerability Database SB2026050534

SB2026050534 - Authentication Bypass by Spoofing in Traefik

Published: May 5, 2026

Security Bulletin ID SB2026050534
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 security vulnerability.


1) Authentication Bypass by Spoofing (CVE-ID: CVE-2026-33433)

The vulnerability allows a remote user to spoof identities to backend services.

The vulnerability exists due to authentication bypass by spoofing in the BasicAuth and DigestAuth authentication middlewares when processing requests with a configured non-canonical headerField header name. A remote privileged user can inject a canonical version of the configured header to spoof identities to backend services.

Exploitation requires headerField to be configured with a non-canonical HTTP header name, and backend services to trust that header for authorization decisions.


Remediation

Install update from vendor's website.

References