The Update BureauKB5087053: Cumulative update for .NET Framework, versions 3.5 and 4.8.1, on Windows 10 21H2/22H2, May 2026. Two .NET runtime elevation-of-privilege flaws addressed
In short
The update addresses two elevation-of-privilege vulnerabilities in .NET Framework 3.5 and 4.8.1. A restart might be required if affected files are in use.
Does it affect you? Applies to: Devices running Windows 10, version 21H2 or 22H2, with .NET Framework 3.5 or 4.8.1 installed.
What changes
Technical details
Data sheet · Security · Downloads · Components Click to collapse or expand
Data sheet
- Released
- 2026-05-12
- Classification
- Security Updates
- Type
- Cumulative update
- Restart
- Required
- Replaces
- KB5082419, KB5066130
- Replaced by
- KB5101000
| Version | File version | Channel |
|---|---|---|
| 3.5 | 2.0.50727.9181 | General availability |
| 4.8.1 | 4.8.9334.0 | General availability |
Security
| Vulnerability | Severity | CVSS |
|---|---|---|
|
.NET Elevation of Privilege Vulnerability
|
Important | 7.3 |
|
.NET Elevation of Privilege Vulnerability
|
Important | 7.3 |
Downloads (Microsoft Update Catalog)
x64
Windows 10 Enterprise LTSC 2021 / Windows 10, version 22H2
75.7 MB
x86
Windows 10 Enterprise LTSC 2021 / Windows 10, version 22H2
47.2 MB
Updated components
63 files changed since the previous update for the same versions.
| Top changed components | Files |
|---|---|
| WPF | 42 |
Sources
Updated
Cited passages from Microsoft's official notes (2)
-
1.
This security update addresses a Elevation of Privilege vulnerability detailed in [CVE-2026-32177.]
support.microsoft.com -
2.
This security update addresses a Elevation of Privilege vulnerability detailed in [CVE-2026-35433.]
support.microsoft.com
Checked automatically: 8 of 8 checks passed, 2 quoted passages · compared with Microsoft's page on Sep 25, 2026
- Quotes found in the official pages: passed
- Numbers found in the sources: passed
- Vulnerabilities from the dossier only: passed
- Links to allowed domains only: passed
- Every official change covered: passed
- Readable plain text: passed
- Changes confirmed by the file list: passed
- Sources agree: passed
A second AI read the text against the sources: correctness 5/5, clarity 4/5, completeness 5/5. How we work
Published by The Update Bureau. Written with AI from Microsoft's own documents, checked by rules and a second AI. How we work · Report a mistake