The User Profile Builder – Beautiful User Registration Forms, User Profiles & User Role Editor plugin for WordPress is vulnerable to Insecure Direct Object Reference in versions up to, and including, 3.15.5 via the wppb_save_avatar_value() function due to missing validation on a user controlled key. This makes it possible for authenticated attackers, with subscriber-level access and above, to reassign ownership of arbitrary posts and attachments by changing 'post_author'.