An elevation of privilege vulnerability exists when tdx.sys fails to check the length of a buffer prior to copying memory to it.
To exploit the vulnerability, in a local attack scenario, an attacker could run a specially crafted application to elevate the attacker's privilege level. An attacker who successfully exploited this vulnerability could run processes in an elevated context.
However, an attacker must first gain access to the local system with the ability to execute a malicious application in order to exploit this vulnerability.
The security update addresses the vulnerability by changing how tdx.sys validates buffer length.