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.NET Framework 3.5 / 4.7.2 .NET Framework 3.5 / 4.7.2 Security update
Patch Tuesday

KB5066143

KB5066143: Cumulative update for .NET Framework, versions 3.5 and 4.7.2, on Windows 10 1809 and Windows Server 2019, October 2025. Information disclosure flaw in framework components addressed

In short

The update addresses CVE-2025-55248, an information disclosure vulnerability in .NET Framework. A restart is required 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 4.7.2 installed.

File version
2.0.50727.9067 · 4.7.4137.0
Security
1 fixed
Restart
Required

What changes

Fix 1 change

.NET Framework

  • An information disclosure vulnerability is addressed.1
    Addresses CVE-2025-55248 in .NET Framework 3.5 and 4.7.2.

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
KB5065744, KB5049608
Replaced by
KB5082413
VersionFile versionChannel
3.5 2.0.50727.9067 General availability
4.7.2 4.7.4137.0 General availability

Security

1 vulnerability fixed
1 not rated
VulnerabilitySeverityCVSS
CVE-2025-55248
.NET, .NET Framework, and Visual Studio Information Disclosure Vulnerability
 Not rated —

Downloads (Microsoft Update Catalog)

x64 Windows 10 Enterprise LTSC 2019 / Windows Server 2019
84.1 MB
windows10.0-kb5066143-x64.msu Main update · KB5066143 SHA-1: 461230ac…80c2bc
Arm64 Windows 10 Enterprise LTSC 2019
46.8 MB
windows10.0-kb5066143-arm64.msu Main update · KB5066143 SHA-1: b4f00690…d50671
x86 Windows 10 Enterprise LTSC 2019
46.8 MB
windows10.0-kb5066143-x86.msu Main update · KB5066143 SHA-1: 70108255…49ac5c

Updated components

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

Sources

Updated
Cited passages from Microsoft's official notes (1)
  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 5/5, clarity 5/5, 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