TOCTOU Race Condition in Windows Win32K Privilege Escalation

Publication date: 2026-09-08

Last updated on: 2026-09-24

Assigner: Microsoft Corporation

Description

Time-of-check time-of-use (toctou) race condition in Windows Win32K allows an authorized attacker to elevate privileges locally.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-09-08

Last Modified

2026-09-24

Generated

2026-09-29

AI Q&A

2026-09-09

EPSS Evaluated

2026-09-27

NVD

CVE-2026-69779

Affected Vendors & Products

Vendor	Product	Version / Range
microsoft	windows_server_2012	r2
microsoft	windows_server_2012	*
microsoft	windows_10_1607	to 10.0.14393.9512 (exc)
microsoft	windows_10_1607	to 10.0.14393.9512 (exc)
microsoft	windows_10_1809	to 10.0.17763.9245 (exc)
microsoft	windows_10_1809	to 10.0.17763.9245 (exc)
microsoft	windows_10_21h2	to 10.0.19044.7725 (exc)
microsoft	windows_10_21h2	to 10.0.19044.7725 (exc)
microsoft	windows_10_21h2	to 10.0.19044.7725 (exc)
microsoft	windows_10_22h2	to 10.0.19045.7725 (exc)
microsoft	windows_10_22h2	to 10.0.19045.7725 (exc)
microsoft	windows_10_22h2	to 10.0.19045.7725 (exc)
microsoft	windows_11_23h2	to 10.0.22631.7582 (exc)
microsoft	windows_11_23h2	to 10.0.22631.7582 (exc)
microsoft	windows_11_24h2	to 10.0.26100.9445 (exc)
microsoft	windows_11_24h2	to 10.0.26100.9445 (exc)
microsoft	windows_11_25h2	to 10.0.26200.9445 (exc)
microsoft	windows_11_25h2	to 10.0.26200.9445 (exc)
microsoft	windows_11_26h1	to 10.0.28000.2954 (exc)
microsoft	windows_11_26h1	to 10.0.28000.2954 (exc)
microsoft	windows_server_2025	to 10.0.26100.33438 (exc)
microsoft	windows_server_2016	to 10.0.14393.9512 (exc)
microsoft	windows_server_2019	to 10.0.17763.9245 (exc)
microsoft	windows_server_2022	to 10.0.20348.5622 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-367	The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check.

Attack-Flow Graph

Executive Summary

This is a time-of-check time-of-use (TOCTOU) race condition in Windows Win32K. It allows an authorized attacker to elevate their privileges locally by exploiting a timing issue between checking and using a resource.

Impact Analysis

An attacker with local access could exploit this to gain higher privileges on your system, potentially allowing them to install programs, view or delete data, or create new accounts with full user rights.

Mitigation Strategies

Apply the latest Windows security updates from Microsoft to patch the Win32K race condition. Monitor Microsoft's security advisories for updates and restrict local user permissions where possible.

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