CVE-2026-32595 Traefik: BasicAuth Middleware Timing Attack Allows Username Enumeration
An unauthenticated attacker can enumerate valid usernames in Traefik's BasicAuth middleware by observing timing differences in response times.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-32595?
CVE-2026-32595 is a medium-severity vulnerability in Traefik Traefik, published on 20 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-208
Which versions are affected by CVE-2026-32595?
11 open source packages ship an affected version, including github.com/traefik/traefik/v3, github.com/traefik/traefik and github.com/traefik/traefik/v2. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/traefik/traefik/v3 Go | All versions | 3.6.11, 3.7.0-ea.2 |
github.com/traefik/traefik/v3 Go | All versions | 3.6.11 |
github.com/traefik/traefik/v3 Go | All versions | 3.6.11 |
github.com/traefik/traefik/v3 Go | From 3.7.0-ea.1 | 3.7.0-ea.2 |
github.com/traefik/traefik/v3 Go | From 3.7.0-ea.1 | 3.7.0-ea.2 |
github.com/traefik/traefik Go | All versions | None |
5 more packages
github.com/traefik/traefik Go | All versions to 1.7.34 | None |
github.com/traefik/traefik Go | All versions to 1.7.34 | None |
github.com/traefik/traefik/v2 Go | All versions | 2.11.41 |
github.com/traefik/traefik/v2 Go | All versions | 2.11.41 |
github.com/traefik/traefik/v2 Go | All versions | 2.11.41 |
Products include Traefik Traefik.
How do I fix CVE-2026-32595?
Upgrade github.com/traefik/traefik/v3 to a fixed version for your release line: 3.6.11 or 3.7.0-ea.2.
Is CVE-2026-32595 being exploited?
There is no known exploitation of CVE-2026-32595 in the wild and no public exploit code.
Other vulnerabilities in Traefik Traefik
- CVE-2024-45410 HTTP client can remove the X-Forwarded headers in Traefik
- CVE-2026-88877 Traefik v3.7.0 Authentication Bypass via from-to-www-redirect
- CVE-2026-85595 Traefik before v2.11.55 and v3.0.0 through v3.7.10 Authentication Bypass via digestAuth
- CVE-2026-88007 Traefik HTTP/3 Backend NTLM Connection Reuse
- CVE-2026-88009 Traefik: Rootless HTTP/1 request-target routes as "/" but is forwarded verbatim, bypassing path-scoped routing, middleware guards and access logging
Sources
Also known as CLEANSTART-2026-BT02769, GHSA-g3hg-j4jv-cwfr, GO-2026-4792, MINI-5f9h-5q73-m67r, MINI-c5xx-77x5-r6gg, MINI-qv85-6w89-r9mr.