CVE-2026-3371: Tutor LMS <= 3.9.7 - Authenticated (Subscriber+) Insecure Direct Object Reference to Arbitrary Course Content Modification

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.