https://wccftech.com/kb5003173-is-out-for-windows-10-21h1-users-insiders-only/

Microsoft has released Windows 10 21H1 Build 19043.985 (KB5003173) for Insiders in the Beta and Release Preview Channels who are currently testing the upcoming May 2021 Update. Today's security update includes the following quality improvements:

Security updates to Windows App Platform and Frameworks, the Windows Kernel, Windows Media, the Microsoft Scripting Engine, and the Windows Silicon Platform.