The Update BureauKB5049608: Cumulative update for .NET Framework, versions 3.5 and 4.7.2, on Windows 10 1809 and Windows Server 2019, January 2025. Closes a .NET remote-code-execution flaw and CLR loop issue
In short
The update addresses a remote-code-execution vulnerability in .NET Framework and a rare CLR infinite-loop issue.
Does it affect you? Applies to: Devices running Windows 10, version 1809, or Windows Server 2019 with .NET Framework 3.5 or 4.7.2 installed.
What changes
Technical details
Data sheet · Security · Downloads · Components Click to collapse or expand
Data sheet
- Released
- 2025-01-14
- Classification
- Security Updates
- Type
- Cumulative update
- Restart
- Required
- Replaces
- KB5046268, KB5044016
- Replaced by
- KB5066143
| Version | File version | Channel |
|---|---|---|
| 3.5 | 2.0.50727.9066 | General availability |
| 4.7.2 | 4.7.4126.0 | General availability |
Security
| Vulnerability | Severity | CVSS |
|---|---|---|
|
.NET, .NET Framework, and Visual Studio Remote Code Execution Vulnerability
|
Not rated | — |
Downloads (Microsoft Update Catalog)
x64
Windows 10 Enterprise LTSC 2019 / Windows Server 2019
84.6 MB
Arm64
Windows 10 Enterprise LTSC 2019
47.2 MB
x86
Windows 10 Enterprise LTSC 2019
47.2 MB
Updated components
28 files changed since the previous update for the same versions.
| Top changed components | Files |
|---|---|
| .NET runtime (CLR) | 18 |
Sources
Updated
Cited passages from Microsoft's official notes (2)
-
1.
This security update addresses a remote code execution vulnerability detailed in CVE-2025-21176.
support.microsoft.com -
2.
Addresses an issue where in rare cases where an infinite loop could occur when a thread enters CLR for the first time.
support.microsoft.com
Checked automatically: 7 of 8 checks passed, 2 quoted passages · 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