An elevation of privilege vulnerability exists in .NET Framework which could allow an attacker to elevate their privilege level.To exploit the vulnerability, an attacker would first have to access the local machine, and then run a malicious program.The update addresses the vulnerability by correcting how .NET Framework activates COM objects., aka '.NET Framework Elevation of Privilege Vulnerability'.
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1066