The Update BureauKB5066137: Cumulative update for .NET Framework, versions 3.5 and 4.8, on Windows 10 1809 and Windows Server 2019, October 2025. Information disclosure flaw in .NET runtime addressed
In short
The update addresses an information disclosure vulnerability in .NET Framework 3.5 and 4.8 on Windows 10, version 1809 and Windows Server 2019. A restart might be needed if affected files are in use.
Does it affect you? Applies to: Devices running Windows 10, version 1809 or Windows Server 2019, with .NET Framework 3.5 or 4.8 installed.
What changes
Fix 1 change
.NET Framework
-
An information disclosure vulnerability in .NET Framework is addressed.1
Addresses CVE-2025-55248.
Technical details
Data sheet · Security · Downloads · Components Click to collapse or expand
Data sheet
- Released
- 2025-10-14
- Classification
- Security Updates
- Type
- Cumulative update
- Restart
- Required
- Replaces
- KB5065755, KB5049615
- Replaced by
- KB5082414
| Version | File version | Channel |
|---|---|---|
| 3.5 | 2.0.50727.9067 | General availability |
| 4.8 | 4.8.4798.0 | General availability |
Security
| Vulnerability | Severity | CVSS |
|---|---|---|
|
.NET, .NET Framework, and Visual Studio Information Disclosure Vulnerability
|
Not rated | — |
Downloads (Microsoft Update Catalog)
x64
Windows 10 Enterprise LTSC 2019 / Windows Server 2019
87.5 MB
x86
Windows 10 Enterprise LTSC 2019
49.9 MB
Updated components
2 files changed since the previous update for the same versions.
Sources
Updated
Cited passages from Microsoft's official notes (1)
-
1.
This security update addresses an information disclosure vulnerability detailed in CVE-2025-55248.
support.microsoft.com
Checked automatically: 7 of 8 checks passed, 1 quoted passage · compared with Microsoft's page on Oct 20, 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: not passed
A second AI read the text against the sources: correctness 4/5, 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