CVE-2026-48020
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.78%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 4.0
- 7.8 HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
- EPSS
- 0.78% probability · 54th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-288, CWE-22
- Affected
- traefik/traefik
- Source
- security-advisories@github.com
References
- https://github.com/traefik/traefik/releases/tag/v2.11.48Patch, Release Notes
- https://github.com/traefik/traefik/releases/tag/v3.6.19Patch, Release Notes
- https://github.com/traefik/traefik/releases/tag/v3.7.3Patch, Release Notes
- https://github.com/traefik/traefik/security/advisories/GHSA-xf64-8mw2-4gr2Exploit, Mitigation, Patch, Vendor Advisory
- https://access.redhat.com/errata/RHSA-2026:62260
- https://access.redhat.com/security/cve/CVE-2026-48020
- https://bugzilla.redhat.com/show_bug.cgi?id=2491915
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-48020.json
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.