Academy LMS <= 3.8.0 - Authenticated (Subscriber+) Insecure Direct Object Reference via 'user_id' Parameter

The Academy LMS – WordPress LMS Plugin for Complete eLearning Solution plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 3.8.0 via the 'save_lesson_note', 'get_lesson_note', and 'complete_lesson_video' AJAX handlers due to missing validation on a user controlled key. This makes it possible for authenticated attackers, with Subscriber-level access and above, to read, overwrite, or delete the private lesson notes of any other user (including administrators), and to falsify lesson-completion progress for arbitrary users.