{"id":"CVE-2026-81509","revision":"c4dfb80a136d44c4a3618b43aa5010c0","records":[{"revision":"c4dfb80a136d44c4a3618b43aa5010c0","observedAt":"2026-10-26T18:35:30.824+00:00","statement":{"source":"cve-program","id":"CVE-2026-81509","aliases":[],"title":"Unvalidated r parameter allows post-authentication open redirect","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.","state":0,"publishedAt":"2026-10-26T17:19:15.467+00:00","modifiedAt":"2026-10-26T17:19:15.467+00:00","affected":[{"ecosystem":"Vendor product","name":"nforwardauth","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"nosduco\",\n                    \"product\": \"nforwardauth\",\n                    \"versions\": [\n                        {\n                            \"version\": \"< 1.5.1\",\n                            \"status\": \"affected\"\n                        }\n                    ]\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1,"severity":"MEDIUM"}],"references":["https://github.com/nosduco/nforwardauth/security/advisories/GHSA-q64r-v7j5-6hfg","https://github.com/nosduco/nforwardauth/pull/71","https://github.com/nosduco/nforwardauth/commit/664f2602f9e1459558d1c4c55019f6d48bc64c43","https://github.com/nosduco/nforwardauth/releases/tag/v1.5.1"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-81509","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-81509","identifiers":["CVE-2026-81509"]},"retained":false,"historicalAffected":[]}],"coverage":[]}