October 13, 2020
.NET Framework 4.8
An information disclosure vulnerability exists when the .NET Framework improperly handles objects in memory. An attacker who successfully exploited the vulnerability could disclose contents of an affected system's memory. To exploit the vulnerability, an authenticated attacker would need to run a specially crafted application. The update addresses the vulnerability by correcting how the .NET Framework handles objects in memory.
To learn more about the vulnerabilities, go to the following Common Vulnerabilities and Exposures (CVE).
Quality and reliability improvements
- Addressed an issue with WCF services sometimes failing to start when starting multiple services concurrently.
- 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.
- 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)`.
- 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.
- 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 update
Microsoft is not currently aware of any issues in this update.
How to get this update
Install this update
|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:
Product:Windows 10 Version 1709Classification: Security Updates
For a list of the files that are provided in this update, download the file information for cumulative update .