CRITICAL 9.9 Microsoft

CVE-2021-26867

Windows Hyper-V Remote Code Execution Vulnerability

Microsoft Security Update 2021-Mar: Windows Hyper-V Remote Code Execution Vulnerability

Affected Products

Windows 10 Version 1909 for x64-based Systems
Windows Server, version 1909 (Server Core installation)
Windows 10 Version 2004 for x64-based Systems
Windows Server, version 2004 (Server Core installation)
Windows Server, version 20H2 (Server Core Installation)

References

Published: 2021-03-09 · Source: Microsoft · Feed updated: 2026-08-20

This critical severity vulnerability with a CVSS score of 9.9 was published on 2021-03-09 via Microsoft. Affected: Windows 10 Version 1909 for x64-based Systems, Windows Server, version 1909 (Server Core installation), Windows 10 Version 2004 for x64-based Systems and 2 more.

Risk Timeline

CVE Disclosed2021-03-09 · 1989 days ago

Remediation Resources

Official Advisory

msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26867

NVD / MITRE

nvd.nist.gov/vuln/detail/CVE-2021-26867

Related Vulnerabilities

CVE	Title	Severity	CVSS
CVE-2026-57092	Microsoft Windows VMSwitch Elevation of Privilege Vulnerability	CRITICAL	9.9
CVE-2021-26877	Windows DNS Server Remote Code Execution Vulnerability	CRITICAL	9.8
CVE-2021-26893	Windows DNS Server Remote Code Execution Vulnerability	CRITICAL	9.8
CVE-2021-26894	Windows DNS Server Remote Code Execution Vulnerability	CRITICAL	9.8
CVE-2021-26895	Windows DNS Server Remote Code Execution Vulnerability	CRITICAL	9.8
CVE-2021-26897	Windows DNS Server Remote Code Execution Vulnerability	CRITICAL	9.8

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