CRITICAL 9.0 Microsoft

CVE-2021-26443

Microsoft Virtual Machine Bus (VMBus) Remote Code Execution Vulnerability

Microsoft Security Update 2021-Nov: Microsoft Virtual Machine Bus (VMBus) Remote Code Execution Vulnerability

Affected Products

Windows 10 Version 1809 for x64-based Systems
Windows Server 2019
Windows Server 2019 (Server Core installation)
Windows 10 Version 1909 for x64-based Systems
Windows 10 Version 21H1 for x64-based Systems
Windows Server 2022
Windows Server 2022 (Server Core installation)
Windows 10 Version 2004 for x64-based Systems

References

Published: 2021-11-09 · Source: Microsoft · Feed updated: 2026-08-20

This critical severity vulnerability with a CVSS score of 9.0 was published on 2021-11-09 via Microsoft. Affected: Windows 10 Version 1809 for x64-based Systems, Windows Server 2019, Windows Server 2019 (Server Core installation) and 5 more.

Risk Timeline

CVE Disclosed2021-11-09 · 1745 days ago

Remediation Resources

Official Advisory

msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26443

NVD / MITRE

nvd.nist.gov/vuln/detail/CVE-2021-26443

Related Vulnerabilities

CVE	Title	Severity	CVSS
CVE-2021-26867	Windows Hyper-V Remote Code Execution Vulnerability	CRITICAL	9.9
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

vulnfeed aggregates 11672 vulnerabilities from NVD, CISA KEV, Ubuntu, Debian, Red Hat, Kubernetes, Exploit-DB, OSS-Security, GitHub and OpenStack — updated every 4 hours.