Microsoft Windows Ancillary Function Driver for WinSock Heap-Based Buffer Overflow Vulnerability (CVE-2025-21418)
Severity: high · Patch status: patched · Since 2025-02-11 · CVE-2025-21418
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. CISA added CVE-2025-21418 to its Known Exploited Vulnerabilities catalog on Feb 11, 2025, which means attackers are exploiting it in the wild.
What to do
- Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
- US federal agencies must remediate by Mar 4, 2025 (BOD 22-01); treat that as the outer limit.
Sources
All live incidents on Threat Watch
