Junglewise Threat Intelligence

CVE-2025-21418: Microsoft Windows Ancillary Function Driver for WinSock Heap-Based Buffer Overflow Vulnerability

CVE-2025-21418 · Severity: critical · CVSS 7.8 · Exploited in the wild · Published 2025-02-11

Technologies: Microsoft Windows, Microsoft Windows 10, Microsoft Windows 11, Microsoft Windows Server. Vendors: Microsoft.

Executive brief

The Microsoft Windows Ancillary Function Driver (AFD) for WinSock contains a heap-based buffer overflow vulnerability. A local attacker can exploit this flaw to escalate privileges and gain SYSTEM-level access on affected Windows operating systems.

Affected products

  • Microsoft Windows 10 1607, 1809, 21H2, 22H2
  • Microsoft Windows 11 22H2, 23H2, 24H2
  • Microsoft Windows Server 2008, 2012, 2016, 2019, 2022, 2025

Timeline

  • 2025-02-11: disclosed
  • 2025-02-11: patched
  • 2025-02-11: kev added: Added to CISA KEV catalog.
  • 2025-02-11: exploited: Reported as exploited in the wild.

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