Note
- Release Date:
February 9, 2021 - Version:
.NET Framework 3.5, 4.7.2 and 4.8
Summary
Security Improvements
This security update addresses a denial of service vulnerability in .NET Framework. For more information please see CVE-2021-24111.
Quality Improvements
For a list of improvements that were released with this update, please see the article links in the Additional Information section of this article.
Known issues in this update
| Symptom | After installing this update, WPF apps may crash with a callstack similar to Exception Info: System.NullReferenceException at System.Windows.Interop.HwndMouseInputProvider.HasCustomChrome(System.Windows.Interop.HwndSource, RECT ByRef) at System.Windows.Interop.HwndMouseInputProvider.GetEffectiveClientRect(IntPtr) at System.Windows.Interop.HwndMouseInputProvider.PossiblyDeactivate(IntPtr, Boolean) at System.Windows.Interop.HwndMouseInputProvider.Dispose()This occurs when disposing an HwndSource whose RootVisual is null, a situation that arises in Visual Studio when docking or splitting windows, and could arise in other apps. |
|---|---|
| Workaround | This issue was resolved in KB4601558 for .NET Framework 4.7.2, and KB4601555 for .NET Framework 4.8. |
Additional information about this update
The following articles contain additional information about this update as it relates to individual product versions.
- 4601060 Description of the Cumulative Update for .NET Framework 3.5 and 4.7.2 for Windows 10, version 1809 and Windows Server, version 2019 (KB4601060)
- 4601055 Description of the Cumulative Update for .NET Framework 3.5 and 4.8 for Windows 10, version 1809 and Windows Server, version 2019 (KB4601055)
| Release Channel | Available | Next Step |
|---|---|---|
| Windows Update and Microsoft Update | 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: Classification: Security Updates |
Information about protection and security
- Protect yourself online: Windows Security support
- Learn how we guard against cyber threats: Microsoft Security