May 12th, 2021

.NET Framework May 2021 Security and Quality Rollup Updates

Tara Overfield
Senior Software Engineer

Yesterday, we released the May 2021 Security and Quality Rollup Updates for .NET Framework.

Quality and Reliability

This release contains the following quality and reliability improvements.

CLR1
  • Addresses an issue where the entire process would be torn down when a NullReferenceException propagated out of an exception filter.
  • Addresses an issue with slowdowns that could occur when making large numbers of devirtualized calls into MarshalByRefObject-derived code.
Windows Forms
  • Addresses an issue in ComboBox drop down item bounding rectangle as exposed to the accessibility tools, where we did not take into account that some items might be scrolled out of view, we had always started counting items from the first visible one, and thus item rectangle location was incorrect.
  • Implemented ScrollItemPattern (IScrollItemProvider (uiautomationcore.h) – Win32 apps | Microsoft Docs) for ComboBox drop down items.
WPF2
  • Addresses an issue with lag responding to typing in TextBox, when spell-checking is enabled that was introduced in an update earlier this year.
  • Addresses an issue with a leak of touch-related resources, including OS handles, when closing a window. The leak only occurs when a touch device is active, and only for windows whose HwndSource is created directly by the app.
  • Addresses a crash when docking a window within Visual Studio, or, more generally, disposing an HwndSource whose RootVisual is null.

1 Common Language Runtime (CLR) 2 Windows Presentation Foundation (WPF)

 

Getting the Update

The Security and Quality Rollup is available via Windows Update, Windows Server Update Services, and Microsoft Update Catalog.

Microsoft Update Catalog

You can get the update via the Microsoft Update Catalog. For Windows 10, NET Framework 4.8 updates are available via Windows Update, Windows Server Update Services, Microsoft Update Catalog. Updates for other versions of .NET Framework are part of the Windows 10 Monthly Cumulative Update.

**Note**: Customers that rely on Windows Update and Windows Server Update Services will automatically receive the .NET Framework version-specific updates. Advanced system administrators can also take use of the below direct Microsoft Update Catalog download links to .NET Framework-specific updates. Before applying these updates, please ensure that you carefully review the .NET Framework version applicability, to ensure that you only install updates on systems where they apply.

The following table is for Windows 10 and Windows Server 2016+ versions.

Product Version Cumulative Update
Windows 10 Version 21H1
.NET Framework 3.5, 4.8 Catalog 4601554
Windows 10, version 20H2 and Windows Server, version 20H2
.NET Framework 3.5, 4.8 Catalog 4601554
Windows 10 2004 and Windows Server, version 2004
.NET Framework 3.5, 4.8 Catalog 4601554
Windows 10 1909 and Windows Server, version 1909
.NET Framework 3.5, 4.8 Catalog 4601556
Windows 10 1809 (October 2018 Update) and Windows Server 2019 5001879
.NET Framework 3.5, 4.7.2 Catalog 4601558
.NET Framework 3.5, 4.8 Catalog 4601555
Windows 10 1803 (April 2018 Update)
.NET Framework 3.5, 4.7.2 Catalog 5003174
.NET Framework 4.8 Catalog 5001842
Windows 10 1607 (Anniversary Update) and Windows Server 2016
.NET Framework 3.5, 4.6.2, 4.7, 4.7.1, 4.7.2 Catalog 5003197
.NET Framework 4.8 Catalog 5001841

The following table is for earlier Windows and Windows Server versions.

Product Version Security and Quality Rollup
Windows 8.1, Windows RT 8.1 and Windows Server 2012 R2 5001881
.NET Framework 3.5 Catalog 4578953
.NET Framework 4.5.2 Catalog 4578956
.NET Framework 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2 Catalog 5001850
.NET Framework 4.8 Catalog 5001845
Windows Server 2012 5001880
.NET Framework 3.5 Catalog 4578950
.NET Framework 4.5.2 Catalog 4578954
.NET Framework 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2 Catalog 5001849
.NET Framework 4.8 Catalog 5001844
Windows 7 SP1 and Windows Server 2008 R2 SP1 5001878
.NET Framework 3.5.1 Catalog 4578952
.NET Framework 4.5.2 Catalog 4578955
.NET Framework 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2 Catalog 5001848
.NET Framework 4.8 Catalog 5001843
Windows Server 2008 5001882
.NET Framework 2.0, 3.0 Catalog 4578951
.NET Framework 4.5.2 Catalog 4578955
.NET Framework 4.6 Catalog 5001848

 

Previous Monthly Rollups

The last few .NET Framework Monthly updates are listed below for your convenience:

Category
.NET

Author

Tara Overfield
Senior Software Engineer

Tara is a Software Engineer on the .NET team. She works on releasing .NET Framework updates.

2 comments

Discussion is closed. Login to edit/delete existing comments.

  • Exames Toxicológicos

    Thank you for taking the time to write to us Appreciate the useful info.

  • Mystery Man

    Yesterday, we released the May 2021 Security and Quality Rollup Updates for .NET Framework.

    That’s strange. On my computers, Windows Update reports that there are no .NET Framework updates available.

    Furthermore, the package that I downloaded from Microsoft Catalog has been digitally signed on 11 February 2021. The package refuses to install anything.