Security Only Update for .NET Framework 3.5, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8 for Windows Server 2012 (KB4566467)

Summary

A remote code execution vulnerability exists in .NET Framework when the software fails to check the source markup of XML file input. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the process responsible for deserialization of the XML content. To exploit this vulnerability, an attacker could upload a specially crafted document to a server utilizing an affected product to process content. The security update addresses the vulnerability by correcting how .NET Framework validates the source markup of XML content.

This security update affects how .NET Framework's System.Data.DataTable and System.Data.DataSet types read XML-serialized data. Most .NET Framework applications will not experience any behavioral change after the update is installed. For more information on how the update affects .NET Framework, including examples of scenarios which may be affected, please see the DataTable and DataSet security guidance document at https://go.microsoft.com/fwlink/?linkid=2132227.

To learn more about the vulnerabilities, go to the following Common Vulnerabilities and Exposures (CVE).

• CVE-2020-1147

Important

• All updates for .NET Framework 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, and 4.7.2 require that the d3dcompiler_47.dll update is installed. We recommend that you install the included d3dcompiler_47.dll update before you apply this update. For more information about the d3dcompiler_47.dll, see KB 4019990.

• If you install a language pack after you install this update, you must reinstall this update. Therefore, we recommend that you install any language packs that you need before you install this update. For more information, see Add language packs to Windows.

Known Issues

Symptoms:

After you apply this update, some applications experience a TypeInitializationException exception when they try to deserialize System.Data.DataSet or System.Data.DataTable instances from the XML within a SQL CLR stored procedure. The stack trace for this exception appears as follows:

System.TypeInitializationException: The type initializer for 'Scope' threw an exception. ---> System.IO.FileNotFoundException: Could not load file or assembly 'System.Drawing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.
     at System.Data.TypeLimiter.Scope.IsTypeUnconditionallyAllowed(Type type)
     at System.Data.TypeLimiter.Scope.IsAllowedType(Type type)
     at System.Data.TypeLimiter.EnsureTypeIsAllowed(Type type, TypeLimiter capturedLimiter)

Resolution:

Install the latest version of this update that was released on October 13th, 2020.

Additional information about this update

The following articles contain additional information about this update as it relates to individual product versions.

• 4565577 Description of the Security Only Update for .NET Framework 3.5 for Windows Server 2012 (KB4565577)

• 4565582 Description of the Security Only Update for .NET Framework 4.5.2 for Windows Server 2012 (KB4565582)

• 4565584 Description of the Security Only Update for .NET Framework 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2 for Windows Server 2012 (KB4565584)

• 4565587 Description of the Security Only Update for .NET Framework 4.8 for Windows Server 2012 (KB4565587)

Information about protection and security

• Protect yourself online: Windows Security support

• Learn how we guard against cyber threats: Microsoft Security