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.NET Framework 4.8 .NET Framework 4.8 Security update
Patch Tuesday

KB5049614

KB5049614: Cumulative update for .NET Framework, version 4.8, on Windows 10 1607 and Windows Server 2016, January 2025. Closes a code-execution flaw and fixes a rare .NET runtime loop

In short

Addresses a remote code execution vulnerability and a rare .NET runtime issue that could cause an infinite loop when a thread enters the CLR for the first time.

Does it affect you? Applies to: Devices running Windows 10, version 1607, or Windows Server 2016 with .NET Framework 4.8 installed.

File version
4.8.4775.0
Security
1 fixed
Restart
Required

What changes

Fixes 2 changes

.NET Framework

  • Addresses a remote code execution vulnerability in .NET Framework.1
    Addresses CVE-2025-21176.

.NET Runtime

  • Addresses a rare issue that could cause an infinite loop when a thread enters the CLR for the first time.2

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
KB5046266, KB5044021
Replaced by
KB5066136
VersionFile versionChannel
4.8 4.8.4775.0 General availability

Security

1 vulnerability fixed
1 important
VulnerabilitySeverityCVSS
CVE-2025-21176
.NET, .NET Framework, and Visual Studio Remote Code Execution Vulnerability
 Important 8.8

Downloads (Microsoft Update Catalog)

x64 Windows 10 Enterprise LTSB 2016 / Windows Server 2016
59.9 MB
windows10.0-kb5049614-x64-ndp48.msu Main update · KB5049614 SHA-1: 6b669fca…148aff
x86 Windows 10 Enterprise LTSB 2016
33.5 MB
windows10.0-kb5049614-x86-ndp48.msu Main update · KB5049614 SHA-1: bfeaddd2…59d852

Updated components

19 files changed since the previous update for the same versions.

Top changed componentsFiles
.NET runtime (CLR)12

Sources

Updated
Cited passages from Microsoft's official notes (2)
  1. 1. This security update addresses a remote code execution vulnerability detailed in CVE-2025-21176. support.microsoft.com
  2. 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: 8 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: 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