Medium · 4.8 CVE-2026-83646 EUVD-2026-99311GHSA-3chv-67xr-9w88

Active Directory Federation Services (AD FS) Spoofing Vulnerability

Published Oct 13, 2026 · Updated Nov 10, 2026 · Assigned by microsoft

Vendor: Microsoft Product: Windows 10 Version 1607 Product: Windows 10 Version 1809 Product: Windows Server 2016 Product: Windows Server 2016 (Server Core installation) Product: Windows Server 2019 Product: Windows Server 2019 (Server Core installation) Product: Windows Server 2022 Product: Windows Server 2025 Product: Windows Server 2025 (Server Core installation) Platform: Windows

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.

Affected products

Vendor	Product	Affected	Fixed
Microsoft	Windows 10 Version 1607	10.0.14393.0 – < 10.0.14393.9612	10.0.14393.9612
Microsoft	Windows 10 Version 1809	10.0.17763.0 – < 10.0.17763.9376	10.0.17763.9376
Microsoft	Windows Server 2016	10.0.14393.0 – < 10.0.14393.9612	10.0.14393.9612
Microsoft	Windows Server 2016 (Server Core installation)	10.0.14393.0 – < 10.0.14393.9612	10.0.14393.9612
Microsoft	Windows Server 2019	10.0.17763.0 – < 10.0.17763.9376	10.0.17763.9376
Microsoft	Windows Server 2019 (Server Core installation)	10.0.17763.0 – < 10.0.17763.9376	10.0.17763.9376
Microsoft	Windows Server 2022	10.0.20348.0 – < 10.0.20348.5761	10.0.20348.5761
Microsoft	Windows Server 2025	10.0.26100.0 – < 10.0.26100.33650	10.0.26100.33650
Microsoft	Windows Server 2025 (Server Core installation)	10.0.26100.0 – < 10.0.26100.33650	10.0.26100.33650

Advisories 2

WID-SEC-2026-3892 Microsoft Windows und Windows Server: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 8, 2026
MSRC-CVE-2026-83646 Active Directory Federation Services (AD FS) Spoofing Vulnerability Microsoft Security Response Center · Oct 13, 2026

References

Active Directory Federation Services (AD FS) Spoofing Vulnerability vendor-advisory patch