CVE-2021-26866
Windows Update Service Elevation of Privilege Vulnerability
Windows Update Service Elevation of Privilege Vulnerability
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Windows Update Service Elevation of Privilege Vulnerability
Windows Update Service Elevation of Privilege Vulnerability
- Record
CVE-2021-26866- CVSS 3.1
- 7.1 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H/E:U/RL:O/RC:C - Updated
- 2026-11-02
EUVDEUVD-2021-13650
Windows Update Service Elevation of Privilege Vulnerability
- Record
EUVD-2021-13650- CVSS 3.1
- 7.1 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H/E:U/RL:O/RC:C - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-8pv9-vfqj-q49w
Windows Update Service Elevation of Privilege Vulnerability
Windows Update Service Elevation of Privilege Vulnerability
- Record
GHSA-8pv9-vfqj-q49w- CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H - Weakness
- CWE-59, CWE-269
- Updated
- 2026-11-02
NVD
Windows Update Service Elevation of Privilege Vulnerability
- Record
CVE-2021-26866- CVSS 3.1
- 7.1 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H - CVSS 3.1
- 6.1 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:H - CVSS 2.0
- 3.6 Low
AV:L/AC:L/Au:N/C:N/I:P/A:P - Weakness
- CWE-59
- Updated
- 2026-11-02
Affected products
- microsoft windows 10 version 1507
- microsoft windows 10 version 1607
- microsoft windows 10 version 1803
- microsoft windows 10 version 1809
- microsoft windows 10 version 1909
- microsoft windows 10 version 2004
- microsoft windows 10 version 20h2
- microsoft windows server 2016
- microsoft windows server 2016 (server core installation)
- microsoft windows server 2019
- microsoft windows server 2019 (server core installation)
- microsoft windows server version 2004
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-2021-26866 is a high vulnerability (CVSS 7.1) in Microsoft Windows 10 Version 1507, published March 11, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.16%, the 67th percentile. No source names a fixed version.