Microsoft have released KB4592438 for Windows Insiders on the beta and release preview channels. The update takes Windows 10 20H2 to build 19042.685 and includes a couple of security updates:
This security update includes quality improvements. Key changes include:
We fixed a security vulnerability by preventing applications that run as a SYSTEM account from printing to “FILE:” ports. To address this issue in the future, make sure your applications or services run as a specific user or service account.
Security updates to Microsoft Edge Legacy, the Microsoft Graphics Component, Windows Media, Windows Fundamentals, and Windows Virtualization.