{"id":"CVE-2026-83646","aliases":["EUVD-2026-99311","GHSA-3chv-67xr-9w88"],"status":"published","title":"Active Directory Federation Services (AD FS) Spoofing Vulnerability","description":"Url redirection to untrusted site ('open redirect') in Active Directory Federation Services (AD FS) allows an authorized attacker to perform spoofing over a network.","severity":{"version":"3.1","score":4.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00374,"percentile":0.31755,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-601"],"published":"2026-10-13T18:59:47Z","modified":"2026-11-10T20:36:01Z","products":[{"vendor":"microsoft","product":"windows 10 version 1607"},{"vendor":"microsoft","product":"windows 10 version 1809"},{"vendor":"microsoft","product":"windows server 2016"},{"vendor":"microsoft","product":"windows server 2016 (server core installation)"},{"vendor":"microsoft","product":"windows server 2019"},{"vendor":"microsoft","product":"windows server 2019 (server core installation)"},{"vendor":"microsoft","product":"windows server 2022"},{"vendor":"microsoft","product":"windows server 2025"},{"vendor":"microsoft","product":"windows server 2025 (server core installation)"},{"vendor":"microsoft","product":"windows_10_1607"},{"vendor":"microsoft","product":"windows_10_1809"},{"vendor":"microsoft","product":"windows_server_2016"},{"vendor":"microsoft","product":"windows_server_2019"},{"vendor":"microsoft","product":"windows_server_2022"},{"vendor":"microsoft","product":"windows_server_2025"}],"references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83646","tags":["vendor-advisory","patch","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-83646"},{"url":"https://github.com/advisories/GHSA-3chv-67xr-9w88"}],"sources":{"cve":[{"id":"CVE-2026-83646","title":"Active Directory Federation Services (AD FS) Spoofing Vulnerability","description":"Url redirection to untrusted site ('open redirect') in Active Directory Federation Services (AD FS) allows an authorized attacker to perform spoofing over a network.","status":"published","published":"2026-10-13T18:59:47.252Z","modified":"2026-11-10T20:36:01.624Z","cvss":[{"version":"3.1","score":4.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C","level":"medium","assessor":"cna"}],"cwes":["CWE-601"],"updated_at":"2026-11-10T22:18:28.707469Z"}],"euvd":[{"id":"EUVD-2026-99311","description":"Url redirection to untrusted site ('open redirect') in Active Directory Federation Services (AD FS) allows an authorized attacker to perform spoofing over a network.","status":"published","published":"2026-10-13T18:59:47Z","modified":"2026-11-10T20:36:01Z","cvss":[{"version":"3.1","score":4.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C","level":"medium"}],"updated_at":"2026-11-10T21:23:23.099302Z"}],"ghsa":[{"id":"GHSA-3chv-67xr-9w88","title":"Url redirection to untrusted site ('open redirect') in Active Directory Federation Services (AD...","description":"Url redirection to untrusted site ('open redirect') in Active Directory Federation Services (AD FS) allows an authorized attacker to perform spoofing over a network.","status":"published","published":"2026-10-13T21:34:31Z","modified":"2026-10-13T21:34:31Z","cvss":[{"version":"3.1","score":4.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N","level":"medium"}],"cwes":["CWE-601"],"updated_at":"2026-11-02T15:13:16.244853Z"}],"nvd":[{"id":"CVE-2026-83646","description":"Url redirection to untrusted site ('open redirect') in Active Directory Federation Services (AD FS) allows an authorized attacker to perform spoofing over a network.","status":"published","published":"2026-10-13T19:20:05.65Z","modified":"2026-10-29T18:18:05.327Z","cvss":[{"version":"3.1","score":4.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"secondary"},{"version":"3.1","score":5.4,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-601"],"updated_at":"2026-11-02T14:12:57.603498Z"}]}}