Auth bypass in Fatedier Frp
CVE-2026-40910
frp is a fast reverse proxy. From 0.43.0 to 0.68.0, frp contains an authentication bypass in the HTTP vhost routing path when routeByHTTPUser is used as part of access control. In proxy-style requests, the routing logic uses the username from Proxy-Authorization to select the routeByHTTPUser backend, while the access control check uses credentials from the regular Authorization header. As a result, an attacker who can reach the HTTP vhost entrypoint and knows or can guess the protected routeByHTTPUser value may access a backend protected by httpUser / httpPassword even with an incorrect Proxy-Authorization password. This issue affects deployments that explicitly use routeByHTTPUser. It does not affect ordinary HTTP proxies that do not use this feature. This vulnerability is fixed in 0.68.1.
Vulnerability class: Broken Authentication
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (19.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 19th percentile — 19.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000
Affected products
- Fatedier Frp — versions < 0.68.1
Weakness classification (CWE)
References
- github.com/fatedier/frp/security/advisories/GHSA-pq96-pwvg-vrr9 (Exploit, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-40910?
- CVE-2026-40910 is a medium-severity vulnerability in Fatedier Frp, classified under Improper Authentication. CVSS score: 6.5/10. Published 2026-04-21.
- How severe is CVE-2026-40910?
- Medium severity. CVSS v3 base score is 6.5 out of 10.