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, 2.7.1 via the 'attempt_delete' function due to missing validation on a user controlled key. This makes it possible for authenticated attackers, with Instructor-level access and above, to delete arbitrary quiz attempts.
https://plugins.trac.wordpress.org/changeset/3098465/
https://plugins.trac.wordpress.org/browser/tutor/trunk/classes/Quiz.php#L1806