RESOLVED: Advisory on February 2019 Security update for Windows 10 update 1809

Final Update 2/19/19 @1:30 PM (PST): This advisory is now resolved with no action needed from Microsoft Customers. The issue was not applicable to any valid or supported configuration. There is no consequence for .NET 4.8 Preview customers.

We strive to share timely information to protect our customer’s productivity, in this case, our finding was thankfully of no consequence for customers on supported configurations.

Update 2/15/19 @3:35 PM (PST): As we continue our investigation, we are finding the issue to be restricted to a limited and isolated set of test-only systems that are using non-official versions of the .NET 4.8 Preview. As of 2/15/19 around 12:00 pm (PST) we further tightened our delivery mechanisms to ensure that the February .NET security updates are only deployed to their expected target systems.

The February 2019 Security and Quality Rollup for Windows 10 update 1809 was released earlier this week. We have received multiple customer reports of issues when a customer has installed .NET Framework 4.8 Preview then installed the February security update, 4483452. These reports are specific to only to the scenario when a customer has installed both .NET Framework 4.8 Preview and the February security update.

We are actively working on investigating and addressing this issue. If you installed the February 2019 security update and have not seen any negative behavior, we recommend that you leave your system as-is but closely monitor it and ensure that you apply upcoming .NET Framework updates.

We will continue to update this post as we have new information.

Guidance

Workaround

Symptoms

"Exception has been thrown by the target of an invocation."