The WP Shortcodes Plugin, also known as Shortcodes Ultimate, is a plugin for WordPress that has a security vulnerability in all versions up to 5.13.3. This vulnerability is called an Insecure Direct Object Reference, and it is caused by a lack of validation of user-controlled keys called ‘key’ and ‘post_id’. This means that if an attacker has at least contributor-level access, they can obtain any post meta values that may contain sensitive information.