CVEvulnerability

CVE-2026-41263

6.3 MEDIUM Published 2026-04-30 Modified 2026-06-17 Official page ↗
Status
Analyzed
Published
2026-04-30
Last modified
2026-06-17
Assigner
[email protected]
CVSS 4.0 ([email protected])
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1 ([email protected])
3.7 LOW — CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Weaknesses
CWE-208

Description

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.

Affected configurations

• traefik traefik (< 2.11.43) • traefik traefik (>= 3.0.0 < 3.6.14) • traefik traefik 3.7.0

Related

Weakness · CWE (1)

  • CWE-208 Observable Timing Discrepancy weakness

References