Microsoft Windows Ancillary Function Driver for WinSock Privilege Escalation Vulnerability

A type confusion vulnerability has been identified in the Windows Ancillary Function Driver for WinSock. This vulnerability allows an authorized attacker to locally elevate privileges. It affects several different versions and ranges of Windows, including various Windows Server versions and Windows 10 and 11 releases.

Impact

Exploitation of this vulnerability could lead to unauthorized privilege escalation, allowing an attacker to gain SYSTEM privileges.

Remediation

Users can apply the security update for this vulnerability, which is available as part of the January 2026 Monthly Rollup for all affected Windows versions. Instructions for downloading this security update can be found in the Microsoft Update Catalog.