A vulnerability in the free version of Bitdefender Antivirus could be exploited by an attacker to get SYSTEM-level permissions, reserved for the most privileged account on a Windows machine. The vulnerability is owed to lack of verification that loaded binaries are signed and come from a trusted location. The root of the issue is the ServiceInstance.dll library that attempts to load the missing DLL library that is the root. The bug was disclosed by SafeBreach Labs on July 17 and on August 14 received validation from the antivirus maker.
Source: https://www.bleepingcomputer.com/news/security/bitdefender-fixes-privilege-escalation-bug-in-free-antivirus-2020/