The ProfileGrid WordPress plugin before 5.9.9.8 does not restrict which group an anonymous visitor may register into through its front-end registration, allowing unauthenticated users to register directly into a privileged group and be granted that groups configured role, up to Administrator when such a group exists, leading to privilege escalation.
The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.