Microsoft · Windows Ancillary Function Driver for WinSock
CVE-2026-68820
Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability
What it is
Use after free in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.
CISA: Microsoft Windows Ancillary Function Driver for WinSock contains a use-after-free vulnerability that allows an authorized attacker to elevate privileges locally.
What to do
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Deadline for US federal agencies: August 25, 2026
More exploited flaws from Microsoft
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| Oct 13, 2026 | Command Injection | Windows | High 8.8 | 9.8% |
| Sep 25, 2026 | Code Injection | SharePoint | High 8.8 | 8.2% |
| Sep 8, 2026 | Link Following | Windows | High 7.8 | 0.4% |
| Sep 8, 2026 | Heap-Based Buffer Overflow | Windows | High 7.8 | 0.4% |
| Aug 26, 2026 | Remote Code Execution | SQL Server | High 8.8 | 57% |
| Aug 18, 2026 | Double Free | Internet Key Exchange (IKE) Service Extensions | Critical 9.8 | 77% |
| Aug 18, 2026 | Weak Authentication | SharePoint | Critical 9.1 | 70% |
| Jul 22, 2026 | Deserialization of Untrusted Data Vulnerability | SharePoint | Critical 9.8 | 3.0% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.