Microsoft Windows Ancillary Function Driver for WinSock Use-After-Free Vulnerability
Null pointer dereference in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.
What happened
Null pointer dereference in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.
CISA lists it as exploited, added 13 May 2025.
Does it affect you
Names Microsoft Windows Server. Enter the product and version you run to place it against the affected range the vendor published.
What to do
- Follow the vendor advisory for the fixed release and any interim mitigation.
msrc.microsoft.com - Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
cisa.gov
CISA’s notes for this entry:
Affected, as published to NVD
- ms-winserver
- Microsoft Windows Server: everything below 10.0.14393.8066
The record
- NVD status
- Analyzed
- Published
- 13 May 2025, last modified 17 Jun 2026 (NVD)
- Severity
- CVSS 3.1 base score 7.8, High — computed here from the vector; NVD states 7.8.
- Vector
- CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness
- CWE-416 Use After Free (NVD; names by MITRE)
- Exploitation
- Listed in CISA’s Known Exploited Vulnerabilities catalogue since 13 May 2025; federal remediation due 03 Jun 2025. CISA entry
- Exploit probability
- EPSS 1.8%, 79th percentile — FIRST, scored 23 Oct 2026. FIRST EPSS
- Vendor
- Microsoft · Windows (CISA)
References on the NVD record
- msrc.microsoft.com/update-guide/vulnerability/CVE-2025-32709Vendor Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-32709US Government Resource
Sources
The verdict above is computed from the products and versions you entered and the affected ranges the vendor published to NVD. It does not inspect your environment, and this site never reports a product as unaffected: why.