Microsoft Windows Ancillary Function Driver for WinSock

What it is

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.

Vendor notices and references

• portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2026-68820
• nvd.nist.gov/vuln/detail/CVE-2026-68820

Description and required action as published by CISA. Full record at NVD.