CVE-2026-41263 (GCVE-0-2026-41263)

Vulnerability from cvelistv5 – Published: 2026-04-30 20:39 – Updated: 2026-05-01 14:22
VLAI
Title
Traefik: BasicAuth middleware: timing side-channel vulnerability
Summary
Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.43, 3.6.14, and 3.7.0-rc.2, there is a timing side-channel vulnerability in Traefik's BasicAuth middleware that allows an attacker to enumerate valid usernames through response-time differences. The variable intended to hold a constant-time fallback secret always resolves to an empty string, causing the constant-time comparison to short-circuit in microseconds rather than performing a full bcrypt evaluation. This restores the original timing oracle and makes it possible to distinguish existing users from non-existing ones by measuring authentication response times. This issue has been patched in versions 2.11.43, 3.6.14, and 3.7.0-rc.2.
Severity
6.3 (Medium)
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-05-01 14:22 UTC
CWE
  • CWE-208 - Observable Timing Discrepancy
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7761 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
traefik traefik Affected: < 2.11.43
Affected: >= 3.0.0-beta1, < 3.6.14
Affected: >= 3.7.0-ea.1, < 3.7.0-rc.2
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

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