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.NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 Optional preview
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KB5092427

KB5092427: Cumulative update for .NET Framework, versions 3.5 and 4.8.1, on Windows 11 25H2, May 2026. Hanging secure requests and incorrect debugger values addressed

In short

Addresses hanging synchronous web requests in certain secure-connection setups and incorrect floating-point values in Visual Studio’s x86 native debugger.

Does it affect you? Applies to: Devices running Windows 11, version 25H2, with .NET Framework 3.5 or 4.8.1 installed.

File version
2.0.50727.9181 · 4.8.9337.0
Restart
Required

What changes

Fixes 2 changes

.NET Libraries

For: Users of applications that make synchronous web requests

  • Synchronous web requests are less likely to hang in certain secure-connection setups.1
    Addresses hangs in synchronous HttpWebRequest connections with certain server configurations.

.NET Runtime

For: Developers using the Visual Studio x86 native debugger

  • Some floating-point values are reported more accurately when stepping through mixed-code applications in the Visual Studio x86 native debugger.1
    Addresses incorrect reporting of certain floating-point values during step operations in the Visual Studio x86 native debugger.

Technical details

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

Data sheet

Released
2026-05-26
Classification
Updates
Type
Cumulative update
Restart
Required
Replaces
KB5074828, KB5067931, KB5066613
Replaced by
KB5100998
VersionFile versionChannel
3.5 2.0.50727.9181 General availability
4.8.1 4.8.9337.0 General availability

Security

No vulnerabilities are listed for this update.

Updated components

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

Top changed componentsFiles
.NET runtime (CLR)12
.NET networking6

Sources

Updated
Cited passages from Microsoft's official notes (1)
  1. 1. Addresses an issue with synchronous HttpWebRequest connections where requests could hang in specific secure connection scenarios with certain server configurations. support.microsoft.com
Checked automatically: 8 of 8 checks passed, 1 quoted passage · compared with Microsoft's page on Sep 25, 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