CVE-2026-48020 Traefik StripPrefix Route-Level Auth Bypass via Path Normalization

What is CVE-2026-48020?

CVE-2026-48020 is a high-severity authentication bypass vulnerability in Traefik Traefik, published on 23 Jun 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. Prior to 2.11.48, 3.6.19, and 3.7.3, there is a high severity vulnerability in Traefik's StripPrefix middleware that allows an unauthenticated attacker to bypass route-level authentication and authorization. When a public router matches on a PathPrefix rule and applies the StripPrefix middleware, a request path containing .. or its percent-encoded form %2e%2e can match the public route at routing time and then, after the prefix is stripped and the path is normalized, resolve to a path served by a separate, authenticated router. As a result, an attacker can reach protected backend paths — such as admin or internal configuration endpoints — without satisfying the authentication middleware attached to the protected router. This vulnerability is fixed in 2.11.48, 3.6.19, and 3.7.3.

Weakness: CWE-22, CWE-288

Which versions are affected by CVE-2026-48020?

9 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.

Products include Traefik Traefik.

How do I fix CVE-2026-48020?

Upgrade github.com/traefik/traefik/v3 to a fixed version for your release line: 3.6.19 or 3.7.3.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2026-48020 being exploited?

There is no known exploitation of CVE-2026-48020 in the wild and no public exploit code.

Public exploit code: 1 proofs of concept on GitHub.

Other vulnerabilities in Traefik Traefik

• CVE-2024-45410 HTTP client can remove the X-Forwarded headers in Traefik Critical 9.8
• CVE-2026-88877 Traefik v3.7.0 Authentication Bypass via from-to-www-redirect Critical 9.3
• CVE-2026-85595 Traefik before v2.11.55 and v3.0.0 through v3.7.10 Authentication Bypass via digestAuth Critical 9.3
• CVE-2026-88007 Traefik HTTP/3 Backend NTLM Connection Reuse Critical 9.1
• CVE-2026-88009 Traefik: Rootless HTTP/1 request-target routes as "/" but is forwarded verbatim, bypassing path-scoped routing, middleware guards and access logging High 8.8

All Traefik Traefik vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as CLEANSTART-2026-RL56372, GHSA-xf64-8mw2-4gr2, GO-2026-5752, MINI-3qcf-p94h-gmv5, MINI-rh4v-8hcm-54rw, MINI-xh66-5gj9-5h7q and 1 more.