CVE-2026-40369

Windows Kernel Elevation of Privilege Vulnerability

CVE-2026-40369 is fixed in 8 products on 1 platform, first by KB5089549, released May 12, 2026. It is not reported as exploited, but the vendor rates exploitation more likely. Patch Radar priority: Urgent.

Urgent

CVSS

7.8

Important

Exploitation

More likely

Vendor assessment

CISA KEV

Not listed

Not in the Known Exploited Vulnerabilities catalog

EPSS

0.0473

91st percentile

<p>Heap-based buffer overflow in Windows Kernel allows an authorized attacker to elevate privileges locally.</p>

Where it's fixed

Product	Fixed in	Fix	Released
Microsoft
Windows 11 Version 24H2 for ARM64-based Systems		KB5089549	May 12, 2026
Windows 11 Version 24H2 for ARM64-based Systems		KB5089466	May 12, 2026
Windows 11 Version 24H2 for x64-based Systems		KB5089549	May 12, 2026
Windows 11 Version 24H2 for x64-based Systems		KB5089466	May 12, 2026
Windows 11 Version 25H2 for ARM64-based Systems		KB5089549	May 12, 2026
Windows 11 Version 25H2 for ARM64-based Systems		KB5089466	May 12, 2026
Windows 11 Version 25H2 for x64-based Systems		KB5089549	May 12, 2026
Windows 11 Version 25H2 for x64-based Systems		KB5089466	May 12, 2026
Windows 11 Version 26H1 for ARM64-based Systems	28000.2113	KB5089548	May 12, 2026
Windows 11 version 26H1 for x64-based Systems	28000.2113	KB5089548	May 12, 2026
Windows Server 2025	26100.32860	KB5087539	May 12, 2026
Windows Server 2025	26100.32772	KB5087423	May 12, 2026
Windows Server 2025 (Server Core installation)	26100.32860	KB5087539	May 12, 2026
Windows Server 2025 (Server Core installation)	26100.32772	KB5087423	May 12, 2026

Details

Published
May 12, 2026
Weakness
Untrusted Pointer Dereference
Vendor advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40369

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