What’s Vulnerable › Vulnerabilities

CVE-2026-32595: Traefik: BasicAuth Middleware Timing Attack Allows Username Enumeration

• Severity: low (CVSS 3.7 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-03-20 · updated 2026-06-17
• Weakness: CWE-208

Description

Traefik is an HTTP reverse proxy and load balancer. Versions 2.11.40 and below, 3.0.0-beta1 through 3.6.11, and 3.7.0-ea.1 comtain BasicAuth middleware that allows username enumeration via a timing attack. When a submitted username exists, the middleware performs a bcrypt password comparison taking ~166ms. When the username does not exist, the response returns immediately in ~0.6ms. This ~298x timing difference is observable over the network and allows an unauthenticated attacker to reliably distinguish valid from invalid usernames. This issue is patched in versions 2.11.41, 3.6.11 and 3.7.0-ea.2.

Affected products

• Traefik: before 2.11.41; from 3.0.0 through 3.6.11; 3.7.0-ea1 — fixed in 2.11.41

How to fix

Upgrade to a fixed version: Traefik 2.11.41. Check the vendor advisory for mitigations.

References

• https://github.com/traefik/traefik/releases/tag/v2.11.41
• https://github.com/traefik/traefik/releases/tag/v3.6.11
• https://github.com/traefik/traefik/releases/tag/v3.7.0-ea.2
• https://github.com/traefik/traefik/security/advisories/GHSA-g3hg-j4jv-cwfr

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