Problem with client connections to SQL Server 2019 after installing KB5020695

Question

We have a serious issue with connections to a SQL server 2019 instance. On all clients that have installed the update: KB5020695 (or the equivalent for the other operating systems), the applications fail during sql read/ write giving unrecoverable errors. All clients without the update are fine, and the clients that are now failing were ok before installing the update. Anyone any ideas as to how to overcome the problem?

The text of the KB states: This security update addresses a vulnerability which exists in System.Data.SqlClient and Microsoft.Data.SqlClient libraries where a timeout occurring under high load can cause incorrect data to be returned as the result of an asynchronously executed query or command.

Answer 1

Hi @Derek Bretherton ,
Try upgrading your version of .net framework. The possible reason can be seen in this link: https://vulners.com/mskb/KB5020695.
And you download .net framework in this link: https://dotnet.microsoft.com/en-us/download/dotnet-framework

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