April 12, 2022-KB5012120 Cumulative Update for .NET Framework 3.5 and 4.8 for Windows 10, version 1909

Winforms

- Addresses a leak of IRawElementProviderSimple objects which was introduced in .NET Framework 4.8. This is an opt-in fix, add the following compatibility switch to the app.config file in order to dispose the accessible objects:

<runtime>

              <!-- AppContextSwitchOverrides values are in the form of 'key1=true|false;key2=true|false  -->

              <AppContextSwitchOverrides value="Switch.System.Windows.Forms.DisconnectUiaProvidersOnWmDestroy=true"/>

       </runtime>

Note: that when the accessibility server application opts into this fix, the accessibility client will receive errors when accessing the disconnected provider. This is expected because the corresponding control window is destroyed. Previous behavior where the provider was returning information for destroyed controls was incorrect.

NET Libraries

- Addresses an issue when Ssl negotiation can hang indefinitely when client certificates are used when TLS 1.3 is negotiated. Before the change renegotiation (PostHandshakeAuthentiction) would fail and SslStream or HttpWebRequest would observe a timeout.

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 10, version 1909

Classification: Security Updates