The Tutor LMS – eLearning and online course solution plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 3.9.7. This is due to missing authorization checks in the save_course_content_order() private method, which is called unconditionally by the tutor_update_course_content_order AJAX handler. While the handler's content_parent branch includes a can_user_manage() check, the save_course_content_order() call processes attacker-supplied tutor_topics_lessons_sorting JSON without any ownership or capability verification. This makes it possible for authenticated attackers with Subscriber-level access or above to detach lessons from topics, reorder course content, and reassign lessons between topics in any course, including admin-owned courses, by sending a crafted AJAX request with manipulated topic and lesson IDs.