CVE-2025-21418
KEVMicrosoft Windows Ancillary Function Driver for WinSock Heap-Based Buffer Overflow Vulnerability
Description
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.
Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability
CVSS 3.1 vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HPublishedFeb 11, 2025
Last modifiedJun 17, 2026
Added to KEVFeb 11, 2025
Remediation dueMar 4, 2025
References
- msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21418PatchVendor Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-21418US Government Resource
0 recent articles mention this CVE
69
Risk assessment · High
Actively exploited. Patch immediately.
- Exploitation
- Confirmed in the wild (CISA KEV)
- Federal remediation deadline
- Overdue by 603 days
- CVSS
- 7.8 HIGH
- EPSS (30-day exploit probability)
- 2.1% · top 18% of all CVEs
- Weakness
- CWE-122
Recommended actions
- 1.Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
- 2.Treat as emergency change: patch or isolate internet-facing instances first.
- 3.Hunt for compromise: review logs for the disclosure window, not just from the patch date.
Assessment is derived automatically from the live signals above; verify against your own asset inventory.