Skip to the content
The Update Bureau
.NET Framework 3.5 / 4.8.1 .NET Framework 3.5 / 4.8.1 Optional preview
Preview

KB5045934

KB5045934: Cumulative update for .NET Framework, versions 3.5 and 4.8.1, on Windows 11 24H2 and Windows Server 2025, November 2024. ASP.NET compilation errors and rare CLR loops addressed

In short

Addresses several .NET reliability issues, including a Visual Studio ASP.NET compilation error and a rare CLR infinite loop. It adds no new security improvements.

Does it affect you? Applies to: Devices running Windows 11, version 24H2, or Windows Server 2025 with .NET Framework 3.5 or 4.8.1 installed.

File version
2.0.50727.9179 · 4.8.9282.0
Restart
Required
Review notes Additional details from the official release notes (1) Read note
  • What changes The update addresses cases where incorrect interface-call devirtualization could occur when JIT optimizations are enabled.

The official sources are linked at the end of the page.

What changes

Fixes 7 changes

ASP.NET

Verified in package

For: Visual Studio developers

  • Addresses an error during design-time compilation of .NET Framework ASP.NET projects in Visual Studio.1
    The error is “The type initializer for ‘System.Web.UI.Util’ threw an exception.”

CLR

5 items
  • Addresses a rare case where a thread entering the CLR for the first time could cause an infinite loop.2
  • Addresses an issue that could cause an incorrect interface call when JIT optimizations are enabled.3
    The issue involves incorrect interface call devirtualization when JIT optimizations are enabled.
  • Addresses a security feature bypass issue involving SecUtility.RandomByte.4
  • Addresses an information disclosure issue involving the performance counter.5
  • Addresses out-of-memory exceptions during garbage collection in applications running under job limits.6

.NET Fundamentals

For: .NET developers

  • Addresses an issue retrieving a particular user's group membership.7
    The issue involves the .NET API UserPrincipal.GetAuthorizationGroups.

Technical details

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

Data sheet

Released
2024-11-12
Classification
Updates
Type
Cumulative update
Restart
Required
Replaced by
KB5048162
VersionFile versionChannel
3.5 2.0.50727.9179 General availability
4.8.1 4.8.9282.0 General availability

Security

No vulnerabilities are listed for this update.

Downloads (Microsoft Update Catalog)

x64 Windows 11, version 24H2 / Windows Server 2025
71.2 MB
windows11.0-kb5045934-x64-ndp481.msu Main update · KB5045934 SHA-1: fa9c3adf…0184c5
Arm64 Windows 11, version 24H2 / Windows Server 2025
87.7 MB
windows11.0-kb5045934-arm64-ndp481.msu Main update · KB5045934 SHA-1: e45dffa5…ae7069

Updated components

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

Top changed componentsFiles
.NET runtime (CLR)12
ASP.NET10
Windows Forms2

Verified in package: changed files confirm ASP.NET.

Sources

Updated
Cited passages from Microsoft's official notes (7)
  1. 1. Addresses an issue where "The type initializer for ‘System.Web.UI.Util’ threw an exception." error with design-time compilation in Visual Studio for .NET Framework ASP.Net projects. support.microsoft.com
  2. 2. Address an issue where in rare cases where an infinite loop could occur when a thread enters CLR for the first time. support.microsoft.com
  3. 3. Address an issue in cases where incorrect interface call devirtualization could occur when JIT optimizations are enabled. support.microsoft.com
  4. 4. Addresses an issue with a security feature bypass vulnerability when using SecUtility.RandomByte. support.microsoft.com
  5. 5. Addresses an issue with information disclosure with the performance counter. support.microsoft.com
  6. 6. Addresses an issue with out of memory exceptions during garbage collection while running applications running under job limits. support.microsoft.com
  7. 7. Addresses an issue with .NET API UserPrincipal.GetAuthorizationGroups to retrieve the Membership of a particular user. support.microsoft.com
Checked automatically: 8 of 8 checks passed, 7 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 4/5, 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