Weak Authentication in Microsoft Windows and Windows Server - CVE-2026-83674
Published: October 14, 2026
Vulnerability identifier: #VU154824
CSH Severity: Medium
CVSS v4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-83674
CWE-ID: CWE-1390
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to perform spoofing.
The vulnerability exists due to weak authentication in Active Directory Federation Services (AD FS) when handling authentication over a network. A remote attacker can exploit the weak authentication to perform spoofing.
Successful exploitation requires a deep understanding of the system and depends on factors that may include the environment, system configuration, and additional security measures.
Affected software
Microsoft Windows
Windows Server
Windows Server
How to mitigate CVE-2026-83674
Install security update from vendor's website.
Microsoft Windows - addressed in versions 10 1607 10.0.14393.9612, 10 1809 10.0.17763.9376
Windows Server - addressed in versions 2016 10.0.14393.9612, 2019 10.0.17763.9376, 2022 10.0.20348.5761, 2025 10.0.26100.33650
Windows Server - addressed in versions 2016 10.0.14393.9612, 2019 10.0.17763.9376, 2022 10.0.20348.5761, 2025 10.0.26100.33650