CVE-2026-21248

Windows Hyper-V Remote Code Execution Vulnerability

State: Published
Severity: 7.3 High
Published: Feb 10, 2026
Updated: Aug 19, 2026
Reserved: Dec 11, 2025

Description

Heap-based buffer overflow in Windows Hyper-V allows an authorized attacker to execute code locally.

Scores

CVSS	Score	Vector	Source
3.1	7.3 High	CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C	microsoft

Weaknesses

CWE-122 Heap-based Buffer Overflow

Affected Products

Product	Versions
Windows 10 Version 1607Microsoft	10.0.14393.0 to before 10.0.14393.8868Affected
Windows 10 Version 1809Microsoft	10.0.17763.0 to before 10.0.17763.8389Affected
Windows 10 Version 21H2Microsoft	10.0.19044.0 to before 10.0.19044.6937Affected
Windows 10 Version 22H2Microsoft	10.0.19045.0 to before 10.0.19045.6937Affected
Windows 11 version 22H3Microsoft	10.0.22631.0 to before 10.0.22631.6649Affected
Windows 11 Version 23H2Microsoft	10.0.22631.0 to before 10.0.22631.6649Affected
Windows 11 Version 24H2Microsoft	10.0.26100.0 to before 10.0.26100.7840Affected
Windows 11 Version 25H2Microsoft	10.0.26200.0 to before 10.0.26200.7840Affected
Windows 11 version 26H1Microsoft	10.0.28000.0 to before 10.0.28000.1575Affected
Windows 11 Version 26H1Microsoft	10.0.28000.0 to before 10.0.28000.1575Affected
Windows Server 2016Microsoft	10.0.14393.0 to before 10.0.14393.8868Affected
Windows Server 2016 (Server Core installation)Microsoft	10.0.14393.0 to before 10.0.14393.8868Affected
Windows Server 2019Microsoft	10.0.17763.0 to before 10.0.17763.8389Affected
Windows Server 2019 (Server Core installation)Microsoft	10.0.17763.0 to before 10.0.17763.8389Affected
Windows Server 2022Microsoft	10.0.20348.0 to before 10.0.20348.4773Affected
Windows Server 2022, 23H2 Edition (Server Core installation)Microsoft	10.0.25398.0 to before 10.0.25398.2149Affected
Windows Server 2025Microsoft	10.0.26100.0 to before 10.0.26100.32370Affected
Windows Server 2025 (Server Core installation)Microsoft	10.0.26100.0 to before 10.0.26100.32370Affected

References

Windows Hyper-V Remote Code Execution Vulnerabilityvendor-advisorypatch

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