2020-10 Cumulative Update for Windows 10 Version 20H2 for x64-based Systems (KB4579311) rolling out now. Also includes 2020-10 Cumulative Update for .NET Framework 3.5 and 4.8 for Windows 10, version 20H2 for x64 (KB4578968).
An information disclosure vulnerability exists when the .NET Framework improperly handles objects in memory. An attacker who successfully exploited the vulnerability could disclose contents of an affected system’s memory. To exploit the vulnerability, an authenticated attacker would need to run a specially crafted application. The update addresses the vulnerability by correcting how the .NET Framework handles objects in memory.