CVE-2021-26443

Microsoft Virtual Machine Bus (VMBus) Remote Code Execution Vulnerability

CVSS v3 9.0 CRITICAL
CVSS v2.0 7.7 HIGH

9.0^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 2.3 / Impact : 6.0

Attack Vector ADJACENT_NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope CHANGED

7.7^/10

CVSS v2.0 : HIGH

Vector : AV:A/AC:L/Au:S/C:C/I:C/A:C

Exploitability : 5.1 / Impact : 10.0

Access Vector ADJACENT_NETWORK

Access Complexity LOW

Authentication SINGLE

Confidentiality Impact COMPLETE

Integrity Impact COMPLETE

Availability Impact COMPLETE

References

Link	Resource
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26443
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26443	Patch Vendor Advisory

Configurations

Configuration 1 (hide)

OR	cpe:2.3:o:microsoft:windows_10:20h2::::::x64:
	cpe:2.3:o:microsoft:windows_10:21h1::::::x64:
	cpe:2.3:o:microsoft:windows_10:1809::::::x64:
	cpe:2.3:o:microsoft:windows_10:1909::::::x64:
	cpe:2.3:o:microsoft:windows_11:-::::::x64:
	cpe:2.3:o:microsoft:windows_server_2016:20h2:::::::*
	cpe:2.3:o:microsoft:windows_server_2016:2004:::::::*
	cpe:2.3:o:microsoft:windows_server_2019:-:::::::*
	cpe:2.3:o:microsoft:windows_server_2022:-:::::::*

History

No history.

Information

Published : 2021-11-10 01:16

Updated : 2026-08-19 17:17

NVD link : CVE-2021-26443

Mitre link : CVE-2021-26443

CVE.ORG link : CVE-2021-26443

JSON object : View

Products Affected

microsoft

windows_11
windows_10
windows_server_2019
windows_server_2016
windows_server_2022

CWE

NVD-CWE-noinfo

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"HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 6.0, "exploitabilityScore": 2.3}, {"type": "Secondary", "source": "nvd@nist.gov", "cvssData": {"scope": "CHANGED", "version": "3.1", "baseScore": 9.0, "attackVector": "ADJACENT_NETWORK", "baseSeverity": "CRITICAL", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 6.0, "exploitabilityScore": 2.3}]}, "affected": [{"source": "secure@microsoft.com", "affectedData": [{"vendor": "Microsoft", "product": "Windows 10 Version 1809", "versions": [{"status": "affected", "version": "10.0.17763.0", "lessThan": "10.0.17763.2300", "versionType": "custom"}], "platforms": ["x64-based Systems"]}, {"vendor": "Microsoft", "product": "Windows 10 Version 1909", "versions": [{"status": "affected", "version": "10.0.0", "lessThan": "10.0.18363.1916", "versionType": "custom"}], "platforms": ["x64-based Systems"]}, {"vendor": "Microsoft", "product": "Windows 10 Version 2004", "versions": [{"status": "affected", "version": "10.0.0", "lessThan": "10.0.19041.1348", "versionType": "custom"}], "platforms": ["x64-based Systems"]}, {"vendor": "Microsoft", "product": "Windows 10 Version 21H1", "versions": [{"status": "affected", "version": "10.0.0", "lessThan": "10.0.19043.1348", "versionType": "custom"}], "platforms": ["x64-based Systems"]}, {"vendor": "Microsoft", "product": "Windows 11 version 21H2", "versions": [{"status": "affected", "version": "10.0.22000.0", "lessThan": "10.0.22000.318", "versionType": "custom"}], "platforms": ["x64-based Systems"]}, {"vendor": "Microsoft", "product": "Windows Server 2019", "versions": [{"status": "affected", "version": "10.0.17763.0", "lessThan": "10.0.17763.2300", "versionType": "custom"}], "platforms": ["x64-based Systems"]}, {"vendor": "Microsoft", "product": "Windows Server 2019 (Server Core installation)", "versions": [{"status": "affected", "version": "10.0.17763.0", "lessThan": "10.0.17763.2300", "versionType": "custom"}], "platforms": ["x64-based Systems"]}, {"vendor": "Microsoft", "product": "Windows Server 2022", "versions": [{"status": "affected", "version": "10.0.20348.0", "lessThan": "10.0.20348.350", "versionType": "custom"}], "platforms": ["x64-based Systems"]}, {"vendor": "Microsoft", "product": "Windows Server version 2004", "versions": [{"status": "affected", "version": "10.0.0", "lessThan": "10.0.19041.1348", "versionType": "custom"}], "platforms": ["x64-based Systems"]}, {"vendor": "Microsoft", "product": "Windows Server version 20H2", "versions": [{"status": "affected", "version": "10.0.0", "lessThan": "10.0.19041.1348", "versionType": "custom"}], "platforms": ["x64-based Systems"]}]}], "published": "2021-11-10T01:16:35.060", "references": [{"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26443", "source": "secure@microsoft.com"}, {"url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26443", "tags": ["Patch", "Vendor Advisory"], "source": "af854a3a-2127-422b-91ae-364da2661108"}], "vulnStatus": "Modified", "weaknesses": [{"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "NVD-CWE-noinfo"}]}], "descriptions": [{"lang": "en", "value": "Microsoft Virtual Machine Bus (VMBus) Remote Code Execution Vulnerability"}, {"lang": "es", "value": "Una vulnerabilidad de Ejecuci\u00f3n de C\u00f3digo Remota en Microsoft Virtual Machine Bus (VMBus)"}], "lastModified": "2026-08-19T17:17:37.557", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:microsoft:windows_10:20h2:*:*:*:*:*:x64:*", "vulnerable": true, "matchCriteriaId": "21074553-EDF2-468D-8E79-C39851B5BC79"}, {"criteria": "cpe:2.3:o:microsoft:windows_10:21h1:*:*:*:*:*:x64:*", "vulnerable": true, "matchCriteriaId": "F8C238FA-B20F-40A5-B861-A8295858F4BE"}, {"criteria": "cpe:2.3:o:microsoft:windows_10:1809:*:*:*:*:*:x64:*", "vulnerable": true, "matchCriteriaId": "6CF580BA-6938-40F6-9D86-F43044A6BACA"}, {"criteria": "cpe:2.3:o:microsoft:windows_10:1909:*:*:*:*:*:x64:*", "vulnerable": true, "matchCriteriaId": "61F0792D-7587-4297-8EE7-D4DC3A30EE84"}, {"criteria": "cpe:2.3:o:microsoft:windows_11:-:*:*:*:*:*:x64:*", "vulnerable": true, "matchCriteriaId": "5D7F7DDB-440E-42CD-82F4-B2C13F3CC462"}, {"criteria": "cpe:2.3:o:microsoft:windows_server_2016:20h2:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "4A190388-AA82-4504-9D5A-624F23268C9F"}, {"criteria": "cpe:2.3:o:microsoft:windows_server_2016:2004:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "0B60D940-80C7-49F0-8F4E-3F99AC15FA82"}, {"criteria": "cpe:2.3:o:microsoft:windows_server_2019:-:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "DB79EE26-FC32-417D-A49C-A1A63165A968"}, {"criteria": "cpe:2.3:o:microsoft:windows_server_2022:-:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "821614DD-37DD-44E2-A8A4-FE8D23A33C3C"}], "operator": "OR"}]}], "sourceIdentifier": "secure@microsoft.com"}