{"id":"CVE-2026-81509","published":"2026-10-26T18:18:46.367","lastModified":"2026-10-26T20:18:37.683","description":"nforwardauth is a forward auth service that allows the use of a single authentication middleware for multiple sites. Versions prior to 1.5.1 accept an unvalidated `r` query parameter on the `/login` endpoint and use them as the post-authentication redirect destination. An unauthenticated attacker can create a legitimate `nforwardauth` login URL that redirects a victim to an attacker-controlled website after the victim successfully authenticates. This issue may facilitate phishing and other social-engineering attacks by abusing the trust associated with the legitimate authentication domain. This vulnerability does not provide an unauthenticated ForwardAuth bypass. Version 1.5.1 contains a patch.","cvssScore":6.1,"cvssSeverity":"MEDIUM","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","cwes":["CWE-601"],"vendors":[],"products":[],"references":[{"url":"https://github.com/nosduco/nforwardauth/commit/664f2602f9e1459558d1c4c55019f6d48bc64c43","tags":[]},{"url":"https://github.com/nosduco/nforwardauth/pull/71","tags":[]},{"url":"https://github.com/nosduco/nforwardauth/releases/tag/v1.5.1","tags":[]},{"url":"https://github.com/nosduco/nforwardauth/security/advisories/GHSA-q64r-v7j5-6hfg","tags":[]}],"exploitRefs":[{"url":"https://github.com/nosduco/nforwardauth/commit/664f2602f9e1459558d1c4c55019f6d48bc64c43","tags":[]},{"url":"https://github.com/nosduco/nforwardauth/pull/71","tags":[]},{"url":"https://github.com/nosduco/nforwardauth/releases/tag/v1.5.1","tags":[]},{"url":"https://github.com/nosduco/nforwardauth/security/advisories/GHSA-q64r-v7j5-6hfg","tags":[]}],"hasPoc":true,"ai":null}