April 9, 2024-KB5036620 Cumulative Update for .NET Framework 3.5 and 4.8.1 for Windows 11, version 22H2 and Windows 11, version 23H2

2024-04-0907:00:00

Microsoft

support.microsoft.com

update

.net framework

security

reliability

windows 11

7.3 High

CVSS3

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

REQUIRED

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H

8.2 High

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

9.0%

JSON

April 9, 2024-KB5036620 Cumulative Update for .NET Framework 3.5 and 4.8.1 for Windows 11, version 22H2 and Windows 11, version 23H2

Release Date:
April 9, 2024 Version: ** .NET Framework 3.5 and 4.8.1**

The April 9, 2024 update for Windows 11, version 22H2 and Windows 11, version 23H2 includes security and cumulative reliability improvements in .NET Framework 3.5 and 4.8.1. We recommend that you apply this update as part of your regular maintenance routines. Before you install this update, see the Prerequisites and Restart requirement sections.

Summary

Security Improvements CVE-2024-21409 - .NET Framework Remote Code Execution Vulnerability
This security update addresses a remote code execution vulnerability detailed in CVE-2024-21409. .NET Framework Defense in Depth Vulnerability
This security update addresses an issue where version of the OSS zlib library is out of date. .NET Framework Defense in Depth Vulnerability

This security update addresses an issue in AIA fetching process. Quality and Reliability Improvements ASP.NET	- Addresses an issue with JavaScriptSerializer where after installing the January Security and Quality update there is a performance degradation.
CLR1	- Addresses an issue with thread pool recycled lists become unresponsive on multi-CPU-group computers. - Addresses an issue where Interlocked.Read from 32-bit apps are much slower on some computers.
Compiler	- Addresses a problem using the native C# compiler (csc.exe) to compile code making calls to COM interop assemblies.
1Common Language Runtime (CLR)

Known issues in this update

Microsoft is not currently aware of any issues in this update.

How to get this update

Install this updateRelease Channel	Available	Next Step
Windows Update and Microsoft Update	Yes	None. This update will be downloaded and installed automatically from Windows Update.
Windows Update for Business	Yes	None. This update will be downloaded and installed automatically from Windows Update.
Microsoft Update Catalog	Yes	To get the standalone package for this update, go to the Microsoft Update Catalog website.
Windows Server Update Services (WSUS)	Yes	This update will automatically sync with WSUS if you configure as follows: Product: Windows 11, version 22H2 and Windows 11, version 23H2Classification: Security Updates File information For a list of the files that are provided in this update, download the file information for cumulative update.

Prerequisites

To apply this update, you must have .NET Framework 3.5 or 4.8.1 installed.

Restart requirement

You must restart the computer after you apply this update if any affected files are being used. We recommend that you exit all .NET Framework-based applications before you apply this update.