April 9, 2024-Security Only Update for .NET Framework 3.5.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8 for Windows Server 2008 R2 SP1 (KB5037127)

Applies to: Microsoft .NET Framework 3.5.1 Microsoft .NET Framework 4.6.2 Microsoft .NET Framework 4.7 Microsoft .NET Framework 4.7.1 Microsoft .NET Framework 4.7.2 Microsoft .NET Framework 4.8

REMINDER Windows Server 2008 R2 SP1 have reached the end of mainstream support and are now in extended security update (ESU) support. Starting in July 2020, there will no longer be optional, non-security releases (known as “C” releases) for this operating system. Operating systems in extended support have only cumulative monthly security updates (known as the “B” or Update Tuesday release). Verify that you have installed the required updates listed in theHow to get this update section before installing this update. Customers who have purchased the Extended Security Update (ESU) for on-premises versions of these operating systems must follow the procedures in KB4522133 to continue receiving security updates after extended support ends on January 14, 2020. For more information on ESU and which editions are supported, see KB4497181. For more information, see the ESU blog.

REMINDER All updates for .NET Framework 4.7.2, 4.7.1, 4.7, 4.6.2, 4.6.1, and 4.6 require that the d3dcompiler_47.dll update is installed. We recommend that you install the included d3dcompiler_47.dll update before you apply this update. For more information about the d3dcompiler_47.dll, see KB 4019990. If you install a language pack after you install this update, you must reinstall this update. Therefore, we recommend that you install any language packs that you need before you install this update. For more information, see Add language packs to Windows.

Summary

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This security update addresses an issue where version of the OSS zlib library is out of date.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.

Known issues in this update

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

Additional information about this update

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

• 5036634 Description of the Security Only Update for .NET Framework 3.5.1 for Windows Server 2008 R2 SP1 (KB5036634)
• 5036631 Description of the Security Only Update for .NET Framework 4.6.2 for Windows Server 2008 R2 SP1 and Windows Server 2008 SP2 (KB5036631)
• 5036632 Description of the Security Only Update for .NET Framework 4.8 for Windows Server 2008 R2 SP1 (KB5036632)

How to get this update

How to obtain help and support for this update

• Help for installing updates: Windows Update FAQ
• Protect yourself online and at home: Windows Security support
• Local support according to your country: International Support