Improper Validation of Specified Type of Input in Microsoft Windows and Windows Server - CVE-2026-25179

Vulnerability identifier: #VU123747

CSH Severity: Low

CVSS v4: 7.3 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-25179

CWE-ID: CWE-1287

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to improper validation of specified type of input in Windows Ancillary Function Driver for WinSock, which leads to security restrictions bypass and privilege escalation.

Microsoft Windows
Windows Server

Install updates from vendor's website.

Microsoft Windows - addressed in versions 10 21H2 10.0.19044.7058, 10 22H2 10.0.19045.7058, 10 1607 10.0.14393.8957, 10 1809 10.0.17763.8511, 11 23H2 10.0.22631.6783, 11 24H2 10.0.26100.7979, 11 24H2 10.0.26100.8037
Windows Server - addressed in versions 2012 R2 6.3.9600.23074, 2012 6.2.9200.25973, 2016 10.0.14393.8957, 2019 10.0.17763.8511, 2022 23H2 10.0.25398.2207, 2022 10.0.20348.4830, 2022 10.0.20348.4893, 2025 10.0.26100.32463, 2025 10.0.26100.32522

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-25179

• Multiple vulnerabilities in Microsoft Windows Ancillary Function Driver for WinSock