Incorrect Permission Assignment for Critical Resource
In GOG Galaxy 1.2.67, there is a service that is vulnerable to weak file/service permissions: GalaxyClientService.exe. An attacker can put malicious code in a Trojan horse GalaxyClientService.exe. After that, the attacker can re-start this service as an unprivileged user to escalate his/her privileges and run commands on the machine with SYSTEM rights.
CWE-732 - Incorrect Permission Assignment for Critical Resource
The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.