{"affected":[{"product":"2FAuth","source":"CNA: GitHub_M","vendor":"Bubka","versions":[{"status":"affected","version":"< 8.0.0"}]}],"cveId":"CVE-2026-63438","cwes":["CWE-287"],"description":"2FAuth is a web app to manage Two-Factor Authentication (2FA) accounts and generate their security codes. Prior to 8.0.0, when AUTHENTICATION_GUARD=reverse-proxy-guard accepts authentication headers from a client that did not pass through a trusted proxy, RemoteUserProvider::retrieveById() creates an account for an unknown REMOTE_USER, promotes the first created account to administrator, and synchronizes the account email from the configured mail header. An unauthenticated remote client can therefore create an administrator on a fresh instance or impersonate and redirect email for a known account, exposing 2FA secrets and administrative functions. This issue is fixed in version 8.0.0.","epss":null,"exploits":[],"kev":null,"metrics":[{"score":9.8,"severity":"critical","source":"CNA: GitHub_M","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}],"modifiedAt":1793996427407,"publishedAt":1793996427407,"references":[{"source":"CNA: GitHub_M","tags":["x_refsource_CONFIRM"],"url":"https://github.com/Bubka/2FAuth/security/advisories/GHSA-r9xx-45m8-mw24"},{"source":"CNA: GitHub_M","tags":["x_refsource_MISC"],"url":"https://github.com/Bubka/2FAuth/commit/43873cbfba445926c7008b4291eeee67752af9e8"},{"source":"CNA: GitHub_M","tags":["x_refsource_MISC"],"url":"https://github.com/Bubka/2FAuth/commit/8a4c395cac97f8b70b4a822639a6ad8a816f927c"},{"source":"CNA: GitHub_M","tags":["x_refsource_MISC"],"url":"https://github.com/Bubka/2FAuth/commit/d9e58ac4a63fbd8a073e423567881c81a87915de"},{"source":"CNA: GitHub_M","tags":["x_refsource_MISC"],"url":"https://github.com/Bubka/2FAuth/releases/tag/v8.0.0"}],"remediation":[],"revision":"6081d76b2a51f91fbaa0c486fdb277d8a17f60dbd1434e0a571e370b97587799","sources":[{"modifiedAt":1793996427407,"name":"CNA: GitHub_M","retrievedAt":1793999371384,"url":"https://www.cve.org/CVERecord?id=CVE-2026-63438"}],"ssvc":null,"status":"published","title":"2FAuth: Reverse Proxy Guard Auto-Creates Users With Admin Promotion From Unauthenticated Header Value","updatedAt":1793999371384}