CVE-2021-26443
Microsoft Virtual Machine Bus (VMBus) Remote Code Execution Vulnerability
Microsoft Virtual Machine Bus (VMBus) Remote Code Execution Vulnerability
Attack profile
How easy it is to exploit
- Attack vector
- Adjacent network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Microsoft Virtual Machine Bus (VMBus) Remote Code Execution Vulnerability
Microsoft Virtual Machine Bus (VMBus) Remote Code Execution Vulnerability
- Record
CVE-2021-26443- CVSS 3.1
- 9.0 Critical
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C - Updated
- 2026-11-02
EUVDEUVD-2021-13248
Microsoft Virtual Machine Bus (VMBus) Remote Code Execution Vulnerability
- Record
EUVD-2021-13248- CVSS 3.1
- 9.0 Critical
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-v594-fc8g-fg3j
Microsoft Virtual Machine Bus (VMBus) Remote Code Execution Vulnerability
Microsoft Virtual Machine Bus (VMBus) Remote Code Execution Vulnerability
- Record
GHSA-v594-fc8g-fg3j- CVSS 3.1
- 9.0 Critical
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H - Updated
- 2026-11-02
NVD
Microsoft Virtual Machine Bus (VMBus) Remote Code Execution Vulnerability
- Record
CVE-2021-26443- CVSS 3.1
- 9.0 Critical
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H - CVSS 2.0
- 7.7 High
AV:A/AC:L/Au:S/C:C/I:C/A:C - Updated
- 2026-11-02
Affected products
- microsoft windows 10 version 1809
- microsoft windows 10 version 1909
- microsoft windows 10 version 2004
- microsoft windows 10 version 21h1
- microsoft windows 11 version 21h2
- microsoft windows server 2019
- microsoft windows server 2019 (server core installation)
- microsoft windows server 2022
- microsoft windows server version 2004
- microsoft windows server version 20h2
- microsoft windows 10
- microsoft windows 11
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History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-26443 is a critical vulnerability (CVSS 9.0) in Microsoft Windows 10 Version 1809, published November 10, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.70%, the 77th percentile. No source names a fixed version.