CVE-2025-21418

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.

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 KEVCVE-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.orgCVE-2025-21418

  Official CVE identifier

  cve.org
• FIRST EPSSCVE-2025-21418

  30-day exploitation probability 1.6%

  first.org
• NIST NVDCVE-2025-21418

  Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability

  nvd.nist.gov

References

• CISA note · msrc.microsoft.com
• CISA note · nvd.nist.gov
• US Government Resource · cisa.gov