CVE-2026-41263
lowTraefik is an HTTP reverse proxy and load balancer.
Vendor / product: Traefik — traefik
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.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N Affected products
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
References
- https://github.com/traefik/traefik/releases/tag/v2.11.43 security-advisories@github.com
- https://github.com/traefik/traefik/releases/tag/v3.6.14 security-advisories@github.com
- https://github.com/traefik/traefik/releases/tag/v3.7.0-rc.2 security-advisories@github.com
- https://github.com/traefik/traefik/security/advisories/GHSA-6x2q-h3cr-8j2h security-advisories@github.com