By default, the plugin allows subscriber-level users to edit and make changes to any and all posts pages - user roles must be specifically blocked from editing posts and pages.
A subscriber, upon registering an account with a site with the WP Pagebuilder plugin, could immediately modify or delete existing content on the site.
Proof of Concept
It is possible for a subscriber-level user to access the editor simply by visiting the post editor’s URL for a given post or page and supplying “wppb_editor” in the “action” parameter e.g. wp-admin/post.php?post=610&action=wppb_editor.