CVE-2021-26443: microsoft windows_10
CVSS: 9.0v3.1CriticalModified
Published 10-11-2021Last modified 19-08-2026
Vulnerability summary
CVE-2021-26443 is a critical (CVSS 9.0) vulnerability in microsoft windows_10. EPSS estimates a 1.70% chance of exploitation in the next 30 days, higher than 76.8% of scored vulnerabilities.
CVSS score
9.0/10
010
Critical · v3.1 (CVE.org)EPSS score
1.70%
0%100%
Low · +0.01 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Timeline
- 10-11-2021PublishedVulnerability first disclosed.
- 19-08-2026Last modifiedVulnerability information updated.
Description
Microsoft Virtual Machine Bus (VMBus) Remote Code Execution Vulnerability
CVSS metrics
3 scores · 2 sources · 2 versionsCritical 9.0Preferred score · CVE.org (CNA)
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:CSourcesAll 2 agree
- NVDNIST9.0CriticalCVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
High 7.7Preferred score · NVD (NIST)
AV:A/AC:L/Au:S/C:C/I:C/A:CSourcesSingle source
EPSS trend
Probability
1.70%
Chance of exploitation in the next 30 days
Percentile
77%
Versus all other CVEs
30-day change
+0.01 pp
From 1.68% on 20-09-2026
20-09-202620-10-2026
EPSS score1.70%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeNo weakness data has been published for this record.
Affected systems
Microsoft13 products
- windows_1020h2 | 21h1 | 1809 | 1909
- windows 10 version 1809≥ 10.0.17763.0, < 10.0.17763.2300
- windows 10 version 1909≥ 10.0.0, < 10.0.18363.1916
- windows 10 version 2004≥ 10.0.0, < 10.0.19041.1348
- windows 10 version 21h1≥ 10.0.0, < 10.0.19043.1348
1 vendor · 13 products
References
2 links- portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26443X Refsource MISCX TransferredPatchVendor Advisory