CVE-2026-33840

Published: May 12, 2026Modified: Jun 1, 2026

7.8

Vector

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

Exploitability: 1.8 / Impact: 5.9

Source: secure@microsoft.com (Secondary)

Description

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Win32K - GRFX allows an authorized attacker to elevate privileges locally.

Affected (7)

Products: Microsoft: Windows 11 24h2, Windows 11 25h2, Windows 11 26h1, Windows Server 2025

4 products

Configuration A

7 vulnerable

Vulnerable Software	Affected Versions
Microsoft Windows 11 24h2	Before 10.0.26100.8390
Microsoft Windows 11 24h2	Before 10.0.26100.8390
Microsoft Windows 11 25h2	Before 10.0.26200.8390
Microsoft Windows 11 25h2	Before 10.0.26200.8390
Microsoft Windows 11 26h1	Before 10.0.28000.2113
Microsoft Windows 11 26h1	Before 10.0.28000.2113
Microsoft Windows Server 2025	Before 10.0.26100.32772

Related CWEs

CWE-416

Use After Free

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

References (1)

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-33840

Source: secure@microsoft.com

Vendor Advisory

Timeline

No history available yet.