CVE tracker / CVE-2026-21231
CVE-2026-21231
CVE-2026-21231 is the Windows Kernel Elevation of Privilege Vulnerability. Microsoft rates it Important, CVSS 7.8. It is not in CISA's Known Exploited Vulnerabilities catalog. Published February 10, 2026.
Risk summary
Microsoft describes it: “Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Kernel allows an authorized attacker to elevate privileges locally.”
How to fix it
Microsoft lists 31 affected products and the update that fixes each:
- KB5075897 · fixed build 10.0.25398.2149
Windows Server 2022, 23H2 Edition (Server Core installation) - KB5075899 · fixed build 10.0.26100.32370
Windows Server 2025, Windows Server 2025 (Server Core installation) - KB5075904 · fixed build 10.0.17763.8389
Windows Server 2019 (Server Core installation), Windows Server 2019, Windows 10 Version 1809 for x64-based Systems, Windows 10 Version 1809 for 32-bit Systems - KB5075906 · fixed build 10.0.20348.4773
Windows Server 2022 (Server Core installation), Windows Server 2022 - KB5075912 · fixed build 10.0.19045.6937, 10.0.19044.6937
Windows 10 Version 22H2 for 32-bit Systems, Windows 10 Version 22H2 for ARM64-based Systems, Windows 10 Version 22H2 for x64-based Systems, Windows 10 Version 21H2 for x64-based Systems, Windows 10 Version 21H2 for ARM64-based Systems, and 1 more - KB5075941 · fixed build 10.0.22631.6649
Windows 11 Version 23H2 for x64-based Systems, Windows 11 Version 23H2 for ARM64-based Systems - KB5075970 · fixed build 6.3.9600.23022
Windows Server 2012 R2 (Server Core installation), Windows Server 2012 R2 - KB5075971 · fixed build 6.2.9200.25923
Windows Server 2012 (Server Core installation), Windows Server 2012 - KB5075999 · fixed build 10.0.14393.8868
Windows Server 2016 (Server Core installation), Windows Server 2016, Windows 10 Version 1607 for x64-based Systems, Windows 10 Version 1607 for 32-bit Systems - KB5077179 · fixed build 10.0.28000.1575
Windows 11 version 26H1 for x64-based Systems, Windows 11 Version 26H1 for ARM64-based Systems - KB5077181 · fixed build 10.0.26100.7840, 10.0.26200.7840
Windows 11 Version 24H2 for x64-based Systems, Windows 11 Version 24H2 for ARM64-based Systems, Windows 11 Version 25H2 for x64-based Systems, Windows 11 Version 25H2 for ARM64-based Systems
What Microsoft changed
- February 10, 2026: Information published.
Details
- Weakness
- CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
- Publicly disclosed (Microsoft)
- No
- Exploited (Microsoft)
- No
- Known exploited (CISA KEV)
- Not listed
- Published
- February 10, 2026
- Last revised
- February 10, 2026
Get told when this changes
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References
From Microsoft, CISA, NVD and FIRST data; the Microsoft details were read when this page was opened. Check the references above before you act.