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.NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 Out-of-band update
Out-of-band

KB5066613

KB5066613

Cumulative update for .NET Framework, versions 3.5 and 4.8.1, on Windows 11 25H2, September 2025

In short

Covers .NET Framework 3.5 and 4.8.1 on Windows 11, version 25H2. A restart might be requested.

Does it affect you? Applies to: Devices running Windows 11, version 25H2, with x64 or Arm64 architecture.

Restart
Required

In detail

  • Other The cumulative update covers .NET Framework 3.5 and 4.8.1 on Windows 11, version 25H2.

Technical details

Data sheet · Security · Downloads · Components Click to collapse or expand

Data sheet

Released
2025-09-30
Classification
Updates
Type
Cumulative update
Restart
Required
Replaced by
KB5066128
VersionFile versionChannel
3.5 General availability
4.8.1 General availability

Security

No vulnerabilities are listed for this update.

Sources

Updated
Checked automatically: 8 of 8 checks passed · compared with Microsoft's page on Oct 21, 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 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