Microsoft Windows Ancillary Function Driver for WinSock Privilege Escalation Vulnerability

A stack-based buffer overflow vulnerability has been identified in the Windows Ancillary Function Driver for WinSock. This vulnerability allows an authorized attacker to elevate privileges locally. The issue arises from a buffer overflow in the driver, which can be exploited to gain higher-level permissions on the system.

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 included in the September 2025 Monthly Rollup, available through the Microsoft Update Catalog. Specific update details can be found in the Microsoft Knowledge Base articles KB5065507, KB5065509, KB5065468, KB5065508, and KB5065511.