OptinMonster <= 2.12.1 - Authenticated (Subscriber+) Sensitive Information Disclosure via Shortcode

The OptinMonster plugin for WordPress is vulnerable to unauthorized access of data due to insufficient post type validation on the 'prepare_campaign' function in versions up to 2.12.1. This makes it possible for authenticated attackers with subscriber-level access, and above, to access potentially sensitive information due to lack of protections and information restrictions that let campaign information or even private post and content information to be leaked.