{"id":"CVE-2018-8340","aliases":["EUVD-2018-19991","GHSA-4rgc-rj2m-g9gr"],"status":"published","title":"A security feature bypass vulnerability exists when Active Directory Federation Services (AD FS)...","description":"A security feature bypass vulnerability exists when Active Directory Federation Services (AD FS) improperly handles multi-factor authentication requests, aka \"AD FS Security Feature Bypass Vulnerability.\" This affects Windows Server 2016, Windows Server 2012 R2, Windows 10 Servers.","severity":{"version":"3.0","score":6.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-08","score":0.07887,"percentile":0.94748,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"published":"2018-08-15T17:00:00Z","modified":"2026-06-17T02:04:39Z","products":[{"vendor":"microsoft","product":"windows 10 servers"},{"vendor":"microsoft","product":"windows server 2012 r2"},{"vendor":"microsoft","product":"windows server 2016"},{"vendor":"microsoft","product":"windows_server_2012"},{"vendor":"microsoft","product":"windows_server_2016"}],"references":[{"url":"http://www.securitytracker.com/id/1041474","tags":["vdb-entry","x_refsource_SECTRACK","x_transferred","Third Party Advisory","VDB Entry"]},{"url":"http://www.securityfocus.com/bid/105029","tags":["vdb-entry","x_refsource_BID","x_transferred","Third Party Advisory","VDB Entry"]},{"url":"https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8340","tags":["x_refsource_CONFIRM","x_transferred","Patch","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2018-8340"},{"url":"https://github.com/advisories/GHSA-4rgc-rj2m-g9gr"}],"sources":{"cve":[{"id":"CVE-2018-8340","description":"A security feature bypass vulnerability exists when Active Directory Federation Services (AD FS) improperly handles multi-factor authentication requests, aka \"AD FS Security Feature Bypass Vulnerability.\" This affects Windows Server 2016, Windows Server 2012 R2, Windows 10 Servers.","status":"published","published":"2018-08-15T17:00:00Z","modified":"2024-08-05T06:54:35.395Z","updated_at":"2026-11-02T14:35:04.172099Z"}],"euvd":[{"id":"EUVD-2018-19991","description":"A security feature bypass vulnerability exists when Active Directory Federation Services (AD FS) improperly handles multi-factor authentication requests, aka \"AD FS Security Feature Bypass Vulnerability.\" This affects Windows Server 2016, Windows Server 2012 R2, Windows 10 Servers.","status":"published","published":"2018-08-15T17:00:00Z","modified":"2024-08-05T06:54:35Z","updated_at":"2026-11-03T02:40:03.169087Z"}],"ghsa":[{"id":"GHSA-4rgc-rj2m-g9gr","title":"A security feature bypass vulnerability exists when Active Directory Federation Services (AD FS)...","description":"A security feature bypass vulnerability exists when Active Directory Federation Services (AD FS) improperly handles multi-factor authentication requests, aka \"AD FS Security Feature Bypass Vulnerability.\" This affects Windows Server 2016, Windows Server 2012 R2, Windows 10 Servers.","status":"published","published":"2022-05-13T01:53:39Z","modified":"2023-02-02T05:02:22Z","cvss":[{"version":"3.0","score":6.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T14:51:25.546182Z"}],"nvd":[{"id":"CVE-2018-8340","description":"A security feature bypass vulnerability exists when Active Directory Federation Services (AD FS) improperly handles multi-factor authentication requests, aka \"AD FS Security Feature Bypass Vulnerability.\" This affects Windows Server 2016, Windows Server 2012 R2, Windows 10 Servers.","status":"published","published":"2018-08-15T17:29:03.907Z","modified":"2026-06-17T02:04:39.677Z","cvss":[{"version":"3.0","score":6.5,"vector":"CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"primary"},{"version":"2.0","score":4,"vector":"AV:N/AC:L/Au:S/C:P/I:N/A:N","level":"medium","assessor":"primary"}],"updated_at":"2026-11-02T14:04:36.842579Z"}]}}