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.NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 Optional preview
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KB5092431

KB5092431: Cumulative update for .NET Framework, versions 3.5 and 4.8.1, on Windows 11 26H1, May 2026. HttpWebRequest hangs and x86 debugger values corrected

In short

Addresses cases where secure web requests hang and where Visual Studio's x86 debugger reports some floating-point values incorrectly.

Does it affect you? Applies to: Arm64 devices running Windows 11, version 26H1, with .NET Framework 4.8.1 installed.

File version
4.8.9337.0
Restart
Required

What changes

Fixes 2 changes

.NET Libraries

  • The update addresses cases where secure web requests could hang with certain server configurations.1
    The issue affects synchronous HttpWebRequest connections in specific secure connection scenarios.

.NET Runtime

For: Developers using Visual Studio's x86 native debugger

  • The update addresses cases where some floating-point values could be reported incorrectly while stepping through mixed-code applications.2
    The issue occurs in the Visual Studio x86 native debugger during step operations.

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
Replaced by
KB5101002
VersionFile versionChannel
3.5 General availability
4.8.1 4.8.9337.0 General availability

Security

No vulnerabilities are listed for this update.

Downloads (Microsoft Update Catalog)

Arm64 Windows 11, version 26H1
55.1 MB
windows11.0-kb5092431-arm64-ndp481.msu Main update · KB5092431 SHA-1: 27e8ec7a…69c7f3

Updated components

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

Top changed componentsFiles
.NET runtime (CLR)18
.NET networking9

Sources

Updated
Cited passages from Microsoft's official notes (2)
  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
  2. 2. Addresses an issue in the Visual Studio x86 native debugger where certain floating-point values could be reported incorrectly during step operations in mixed-code applications. support.microsoft.com
Checked automatically: 8 of 8 checks passed, 2 quoted passages · 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