Release Date:May 14, 2024

Version:.NET Framework 3.5 and 4.8

The May 14, 2024 update for Windows 10, version 1809 and Windows Server 2019 includes security and 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.

Summary

Security Improvements

There are no new security improvements in this release. This update is cumulative and contains all previously released security improvements.

Quality and Reliability Improvements

CLR1

- Addresses an issue where crashes can occur if several threads all concurrently query the ITypeInfo implementation of the same managed type

.NET Libraries

- Addresses an issue where 32-bit platform show a significant response time regression.

- Addresses an issue to use MIST validated implementations of FIPS algorithms.

.NET Fundamentals

- Addresses an issue with wildcard format changes introduced in IIS 10.

WPF2

- Addresses an issue where apps crash when calling GetWindowText and GetWindowTextLength methods.

1Common Language Runtime (CLR)

2Windows Presentation Foundation (WPF)

Additional information about this update

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

  • 5038283 Description of the Cumulative Update for .NET Framework 3.5, 4.7.2 and 4.8 for Windows 10, version 1809 and Windows Server 2019 (KB5038283)

Known issues in this update

Symptom

Microsoft received reports about .NET Framework May cumulative update causing customers to observe runtime exceptions in certain SQL CLR hosted scenarios. These exceptions will manifest with the error message

System.Security.HostProtectionException: Attempted to perform an operation that was forbidden by the CLR host and will contain one of the following frames in the exception stack trace:

System.Security.Cryptography.SHA256Managed..ctor() - or -

System.Security.Cryptography.SHA384Managed..ctor() - or -

System.Security.Cryptography.SHA512Managed..ctor()

This exception is due to a recent change in the implementation of the SHA256Managed, SHA384Managed, and SHA512Managed types in .NET Framework.  Use of the SHA1Managed, HMACSHA1, HMACSHA256, HMACSHA284, and HMACSHA512 types within SQL CLR hosted environments is not impacted.

Workaround

Multiple work arounds options are available.

One option is to mark the assembly which utilizes the SHA256Managed, SHA384Managed, or SHA512Managed types as UNSAFE. This will cause the SQL CLR hosted environment to allow the affected constructors to execute successfully.

Another option is to utilize SQL's built-in HASHBYTES function rather than the .NET Framework's SHA-2 family of APIs. The HASHBYTES function is directly callable from SQL and does not require writing managed code.

Resolution

Microsoft has resolved this issue with update KB5043804.

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.

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 individual .NET Framework product update will be installed, as applicable, by applying the operating system update. For more information about operating system updates see additional information about this update section.

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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