IMPORTANT

This update was originally released in the Security and Quality Rollup that’s dated September 26, 2023.  This update is included in the Security and Quality Rollup that’s dated October 10, 2023.  There is no change to this update with this release on October 10, 2023.  If you have previously installed this update no action is needed.

Release Date:October 10, 2023

Version:.NET Framework 3.5 and 4.8.1

The October 10, 2023 update for Windows 11, version 22H2 and Windows 11, version 23H2 includes 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

There are no new security improvements in this release. This update is cumulative and contains all previously released security improvements.

Quality and Reliability Improvements

ASP.NET

- Addresses an issue with "System.ArgumentException: Illegal characters in path" in some ASP.Net MVC requests.

SqlClient

- Addresses an issue with SQL event source telemetry.

Additional information about this update

The following articles contain additional information about this update as it relates to individual product versions.

  • 5031323 Description of the Cumulative Update for .NET Framework 3.5 and 4.8.1 for Windows 11, version 22H2 for x64 (KB5031323)

  • 5031324 Description of the Cumulative Update for .NET Framework 3.5 and 4.8.1 for Windows 11, version 22H3 for x64 (KB5031324)

Known issues in this update

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

How to get this update

Install this update

Release 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 Products and Classifications as follows:

Product: Windows 11, version 22H2 or Windows 11, version 23H2

Classification: 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.

How to obtain help and support for this update

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