MICROSOFT-CVE-2026-20831

HIGH7.8

Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability

Published Jan 13, 2026

Modified Yesterday

Details

Time-of-check time-of-use (toctou) race condition in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

References

ADVISORY

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20831

CVSS Analysis

CVSS v2.0

7.8

Upstream

CVE-2026-20831

Ecosystems

Timeline

PublishedJan 13, 2026

ModifiedApr 30, 2026