An elevation of privilege vulnerability exists when the Windows Speech Shell Components improperly handle memory. To exploit this vulnerability, an attacker would first have to gain execution on the victim system. An attacker could then run a specially crafted application to elevate privileges. The security update addresses the vulnerability by correcting how the Windows Speech Shell Components handle memory.
https://www.tenable.com/blog/microsoft-s-august-2020-patch-tuesday-addresses-120-cves-cve-2020-1337
https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-1524