Detections
Analytics
CVE-2026-18439
medium
Description
The Tutor LMS – eLearning and online course solution plugin for WordPress is vulnerable to Insecure Direct Object Reference in versions up to, and including, 4.0.7 via the tutor_quiz_builder_save AJAX action due to missing validation that nested question_id, answer_id, deleted_question_ids[], and deleted_answer_ids[] values in the submitted payload belong to a quiz/topic/course the requester is authorized to manage. The handler only validates the top-level course_id, topic_id, and (when supplied) payload['ID'], but the nested identifiers are passed straight into $wpdb->update/DELETE statements in QuizBuilder::save_questions(), QuizBuilder::save_question_answers(), and QuizBuilder::handle_delete(). This makes it possible for authenticated attackers, with Instructor-level access and above, to overwrite the content and re-parent arbitrary quiz questions/answers belonging to other instructors or administrators, and to delete arbitrary quiz question and answer rows.
References
https://plugins.trac.wordpress.org/changeset/3690454/tutor/tags/4.0.8/classes/QuizBuilder.php
https://plugins.trac.wordpress.org/browser/tutor/tags/4.0.3/classes/QuizBuilder.php#L781
https://plugins.trac.wordpress.org/browser/tutor/tags/4.0.3/classes/QuizBuilder.php#L430
https://plugins.trac.wordpress.org/browser/tutor/tags/4.0.3/classes/QuizBuilder.php#L423
https://plugins.trac.wordpress.org/browser/tutor/tags/4.0.3/classes/QuizBuilder.php#L291
https://plugins.trac.wordpress.org/browser/tutor/tags/4.0.3/classes/QuizBuilder.php#L156
https://plugins.trac.wordpress.org/browser/tutor/tags/3.9.10/classes/QuizBuilder.php#L781
https://plugins.trac.wordpress.org/browser/tutor/tags/3.9.10/classes/QuizBuilder.php#L430
https://plugins.trac.wordpress.org/browser/tutor/tags/3.9.10/classes/QuizBuilder.php#L423
https://plugins.trac.wordpress.org/browser/tutor/tags/3.9.10/classes/QuizBuilder.php#L291
https://plugins.trac.wordpress.org/browser/tutor/tags/3.9.10/classes/QuizBuilder.php#L156