CVE-2021-31961 json
Windows InstallService Elevation of Privilege Vulnerability
published 2021-07-14 5 y ago modified 2026-08-10 2 mo ago also EUVD-2021-18833
- cvss
- 6.1
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.8%
- EPSS 0.8% chance of exploitation in 30 days, percentile 57%
- public exploits
- 0
- none known
Summary
Windows InstallService Elevation of Privilege Vulnerability
Patch / fix
- Microsoft Windows 10 Version 1809 10.0.17763.2061
- Microsoft Windows 10 Version 1909 10.0.18363.1679
- Microsoft Windows 10 Version 2004 10.0.19041.1110
- Microsoft Windows 10 Version 20H2 10.0.19042.1110
- Microsoft Windows 10 Version 21H1 10.0.19043.1110
- Microsoft Windows Server 2019 10.0.17763.2061
- Microsoft Windows Server 2019 (Server Core installation) 10.0.17763.2061
- Microsoft Windows Server version 2004 10.0.19041.1110
- Microsoft Windows Server version 20H2 10.0.19042.1110
Exploit prediction
0.81% chance of exploitation in the next 30 days, higher than 57% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 6.1 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H/E:U/RL:O/RC:C |
| CNA | 3.1 | 6.1 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H |
| NVD | 2.0 | 3.6 | AV:L/AC:L/Au:N/C:N/I:P/A:P |
Affected products
- Microsoft Windows 10 Version 1809
- Microsoft Windows 10 Version 1909
- Microsoft Windows 10 Version 2004
- Microsoft Windows 10 Version 20H2
- Microsoft Windows 10 Version 21H1
- Microsoft Windows Server 2019
- Microsoft Windows Server 2019 (Server Core installation)
- Microsoft Windows Server version 2004
- Microsoft Windows Server version 20H2
Classification
- Weakness
-
- CWE-269 Improper Privilege Management
References
-
msrc.microsoft.com
/update-guide/vulnerability/CVE-2021-31961
vendor-advisory, patch
-
portal.msrc.microsoft.com
/en-US/security-guidance/advisory/CVE-2021-31961
patch, vendor-advisory
-
zerodayinitiative.com
/advisories/ZDI-21-818/
third-party-advisory, vdb-entry
Sources
- CVE List CVE-2021-31961
- NVD CVE-2021-31961
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.