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Findings

CVE-2025-21418

Microsoft Windows Ancillary Function Driver for WinSock Heap-Based Buffer Overflow Vulnerability

Published Feb 11, 2025 · updated Jun 17, 2026 · microsoft windows 10 1607

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.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Feb 11, 2025 · Catalog

    Detected

    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.

  2. Feb 11, 2025 · CISA KEV

    Known exploited

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

  3. Mar 4, 2025 · CISA KEV

    Remediation due

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

  4. Jun 17, 2026 · Catalog

    Updated

    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.

Required action

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

CISA due date Mar 4, 2025

Affected

  • cpe microsoft/windows 10 1607version unspecified
  • cpe microsoft/windows 10 1809version unspecified
  • cpe microsoft/windows 10 21h2version unspecified
  • cpe microsoft/windows 10 22h2version unspecified
  • cpe microsoft/windows 11 22h2version unspecified
  • cpe microsoft/windows 11 23h2version unspecified
  • vendor Microsoft Windowsversion unspecified

Sources

  • CISA KEVConfirmed exploitationCVE-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.gov
  • CVE.orgVulnerability recordCVE-2025-21418

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-21418

    30-day exploitation probability 1.6%

    first.org
  • NIST NVDVulnerability recordCVE-2025-21418

    Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability

    nvd.nist.gov

References