ProfileGrid < 6.0.0.0 - Unauthenticated Group Member List Disclosure via pm_get_all_users_from_group

The ProfileGrid WordPress plugin before 6.0.0.0 does not perform authorization checks before returning a group's member list, and registers the handler for unauthenticated users, allowing any unauthenticated visitor to disclose the members and their identifiers of any group, including private or closed ones, bypassing the ProfileGrid WordPress plugin before 6.0.0.0's member-visibility setting.