Skip to the content
The Update Bureau
.NET Framework 3.5 / 4.8 .NET Framework 3.5 / 4.8 Security update
Patch Tuesday

KB5036613

KB5036613: Cumulative update for .NET Framework, versions 3.5 and 4.8, on Windows Server 2022, April 2024. Remote-code flaw addressed; serializer slowdown improved

In short

The update addresses CVE-2024-21409, a .NET Framework remote code execution flaw, and reliability problems in ASP.NET and the CLR.

Does it affect you? Applies to: Windows Server 2022 devices with .NET Framework 3.5 or 4.8 installed.

File version
2.0.50727.9176 · 4.8.4718.0
Security
1 fixed
Restart
Required

What changes

Fixes 5 changes

.NET Framework

3 items

For: Windows Server 2022 devices with .NET Framework 3.5 or 4.8 installed

  • Addresses a remote code execution vulnerability in .NET Framework.1
    CVE-2024-21409.
  • Addresses a security issue involving an outdated OSS zlib library.2
  • Addresses a security issue in the AIA fetching process.3

ASP.NET

Verified in package

For: Devices running applications that use ASP.NET

  • Addresses a performance slowdown involving JavaScriptSerializer after the January Security and Quality update.4

CLR

  • Addresses an issue that could make thread-pool recycled lists unresponsive on computers with multiple CPU groups.5
    CLR means Common Language Runtime.

Technical details

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

Data sheet

Released
2024-04-09
Classification
Security Updates
Type
Cumulative update
Restart
Required
Replaces
KB5034613, KB5033914
Replaced by
KB5039889
VersionFile versionChannel
3.5 2.0.50727.9176 General availability
4.8 4.8.4718.0 General availability

Security

1 vulnerability fixed
1 not rated
VulnerabilitySeverityCVSS
CVE-2024-21409
.NET, .NET Framework, and Visual Studio Remote Code Execution Vulnerability
 Not rated —

Downloads (Microsoft Update Catalog)

x64 Windows Server 2022
66.9 MB
windows10.0-kb5036613-x64-ndp48.msu Main update · KB5036613 SHA-1: e6377591…93ad24

Updated components

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

Top changed componentsFiles
WPF30
.NET runtime (CLR)12
WCF12
ASP.NET10

Verified in package: changed files confirm ASP.NET.

Sources

Updated
Cited passages from Microsoft's official notes (5)
  1. 1. This security update addresses a remote code execution vulnerability detailed in CVE-2024-21409. support.microsoft.com
  2. 2. This security update addresses an issue where version of the OSS zlib library is out of date. support.microsoft.com
  3. 3. This security update addresses an issue in AIA fetching process. support.microsoft.com
  4. 4. Addresses an issue with JavaScriptSerializer where after installing the January Security and Quality update there is a performance degradation. support.microsoft.com
  5. 5. Addresses an issue with thread pool recycled lists become unresponsive on multi-CPU-group computers. support.microsoft.com
Checked automatically: 7 of 8 checks passed, 5 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: not 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