CVE-2026-88010

Medium

Description

Traefik is an open source HTTP reverse proxy and load balancer. From 3.6.11 until 3.7.13, checkPassword in pkg/middlewares/auth/basic_auth.go constructs the BasicAuth singleflight key from the submitted password and stored secret. Concurrent requests for absent usernames therefore coalesce on one key while configured usernames perform separate password hashes, creating an unauthenticated timing discrepancy that reveals whether a username exists. Sequential checks remain cost-equalized, Traefik v2 and Digest authentication are not affected, and the issue does not disclose credentials or bypass authentication. This issue is fixed in version 3.7.13.

SeverityMedium
CVSS6.3
Exploit probability—
ProductTraefik
PublishedSep 22, 2026
First seenSep 22, 2026
Weakness typeCWE-208CWE-208

How to fix

Update
  • Traefik3.7.13 or later
  • traefik traefik3.7.13 or later
  • github.com/traefik/traefik/v33.7.13 or later

Affected products

ProductAffected versionsFixed in
TraefikGo3.6.11 ≤ v < 3.7.133.7.13
github.com/traefik/traefikGoNo range specified, 0 < v—
traefik traefik3.6.11 ≤ v < 3.7.133.7.13
github.com/traefik/traefik/v3Go3.6.11 ≤ v ≤ 3.7.123.7.13

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