HIGH 8.8 Microsoft
CVE-2026-21255
Windows Hyper-V Security Feature Bypass Vulnerability
Microsoft Security Update 2026-Feb: Windows Hyper-V Security Feature Bypass Vulnerability
Affected Products
- Windows 11 Version 26H1 for ARM64-based Systems
- Windows 11 version 26H1 for x64-based Systems
- Windows 10 Version 1809 for x64-based Systems
- Windows Server 2019
- Windows Server 2019 (Server Core installation)
- Windows Server 2022
- Windows Server 2022 (Server Core installation)
- Windows 10 Version 21H2 for x64-based Systems
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21255
- https://nvd.nist.gov/vuln/detail/CVE-2026-21255
This high severity vulnerability with a CVSS score of 8.8 was published on 2026-02-10 via Microsoft. Affected: Windows 11 Version 26H1 for ARM64-based Systems, Windows 11 version 26H1 for x64-based Systems, Windows 10 Version 1809 for x64-based Systems and 5 more.
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