CVE-2025-21418

Vulnerability details

Microsoft Windows Ancillary Function Driver for WinSock contains a heap-based buffer overflow vulnerability that allows for privilege escalation, enabling a local attacker to gain SYSTEM privileges.

Added to CISA KEV: 2025-02-11

Ransomware campaign use: Unknown

CISA due date: 2025-03-04

Defensive guidance from CISA

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

This is the source's required-action field, not an independently validated patch procedure. Refer to the vendor for exact affected versions and fixes.