Description

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

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windows_10_1607

2

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windows_10_22h2

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Vulnerable

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windows_server_2022

Vulnerable

o

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windows_server_2022_23h2

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windows_server_2025

Vulnerable

References

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

Vendor Advisory

Weaknesses

[email protected]

Primary
CWE-367

CVSS impact metrics

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

7.8 · High

Information

Source identifier

[email protected]

Vulnerability status

Analyzed

Published

2026-01-13T18:16:10.977Z

47 hours ago

Last modified

2026-01-15T14:34:16.123Z

3 hours ago