September 16, 2020-KB4576947 Cumulative Update Preview for .NET Framework 3.5 and 4.8 for Windows 10, version 1903, Windows Server, version 1903, Windows 10, version 1909 and Windows Server, version 1909
Applies To
.NETRelease Date:September 16, 2020
Version:.NET Framework 3.5 and 4.8
The September 16, 2020 update for Windows 10, version 1903, Windows Server, version 1903, Windows 10, version 1909 and Windows Server, version 1909 includes cumulative reliability improvements in .NET Framework 3.5 and 4.8. 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.
Quality and reliability improvements
|
WCF1 |
- Addressed an issue with WCF services sometimes failing to start when starting multiple services concurrently. |
|
Winforms |
- Addressed a regression introduced in .NET Framework 4.8, where Control.AccessibleName, Control.AccessibleRole, and Control.AccessibleDescription properties stopped working for the following controls:Label, GroupBox, ToolStrip, ToolStripItems, StatusStrip, StatusStripItems, PropertyGrid, ProgressBar, ComboBox, MenuStrip, MenuItems, DataGridView. - Addressed a regression in accessible name for combo box items for data bound combo boxes. .NET Framework 4.8 started using type name instead of the value of the DisplayMember property as an accessible name, this improvement uses the DisplayMember again. |
|
ASP.NET |
- Disabled resuse of AppPathModifier in ASP.Net control output. - HttpCookie objects in the ASP.Net request context will be created with configured defaults for cookie flags instead of .NET-style primitive defaults to match the behavior of `new HttpCookie(name)`. |
|
SQL |
- Addressed a failure that sometimes occured when a user connects to one Azure SQL database, performed an enclave based operation, and then connected to another database under the same server that has the same Attestation URL and performed an enclave operation on the second server. |
|
CLR2 |
- Added a CLR config variable Thread_AssignCpuGroups (1 by default) that can be set to 0 to disable automatic CPU group assignment done by the CLR for new threads created by Thread.Start() and thread pool threads, such that an app may do its own thread-spreading. - Addressed a rare data corruption that can occur when using new API’s such as Unsafe.ByteOffset<T> which are often used with the new Span types. The corruption could occur when a GC operation is performed while a thread is calling Unsafe.ByteOffset<T> from inside of a loop. - Addressed an issue regarding timers with very long due times ticking down much sooner than expected when the AppContext switch "Switch.System.Threading.UseNetCoreTimer" is enabled. |
1 Windows Communication Foundation (WCF)2 Common Language Runtime (CLR)
Known issues in this security update
ASP.Net applications fail during precompilation with error message
Symptoms After you apply this September 16, 2020 Security and Quality Rollup for .NET Framework 4.8, some ASP.Net applications fail during precompilation. The error message that you receive will likely contain the words “Error ASPCONFIG.”Cause An invalid configuration state in either the “sessionState,” “anonymouseIdentification,” or “authentication/forms” sections of “System.web” configuration. This might occur during build-and-publish routines if configuration transformations leave the Web.config file in an intermediate state for precompilation.Workaround
This issue was resolved in KB4601056.
ASP.Net applications may not deliver cookieless tokens in the URI
Symptoms After you apply this October 1, 2020 Security and Quality Rollup for .NET Framework 4.8, some ASP.Net applications may not deliver cookieless tokens in the URI, possibly resulting in 302-redirect loops or lost or missing session state.Cause The ASP.Net features for Session State, Anonymous Identification, and Forms Authentication all rely on issuing tokens to a web client, and they all allow the option for those tokens to be delivered in a cookie or embedded in the URI for clients that don’t support cookies. The URI-embedding has long been an insecure and disrecommended practice and this KB quietly disables issuing tokens in URI’s unless one of these three features explicitly requests a cookie mode of “UseUri” in configuration. Configurations that specify “AutoDetect” or “UseDeviceProfile” may inadvertently result in attempted and failed embedding of these tokens in the URI.
Workaround
This issue was resolved in KB4601056.
How to obtain and install the update
Install this update
|
Release Channel |
Available |
Next Step |
|
Windows Update and Microsoft Update |
Yes |
To download and install this update, go to Settings > Update & Security > Windows Update, and then select Check for updates. |
|
Microsoft Update Catalog |
Yes |
To get the standalone package for this update, go to the Microsoft Update Catalog website. |
|
Windows Server Update Services (WSUS) |
No |
You can import this update into WSUS manually. See the Microsoft Update Catalog for instructions. |
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 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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Help for installing updates: Windows Update FAQ
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Protect yourself online and at home: Windows Security support
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Local support according to your country: International Support
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