Vulnerability · Published Sep 22, 2026 · Assigned by Wordfence

CVE-2026-18439Tutor LMS <= 4.0.7 - Authenticated (Custom+) Insecure Direct Object Reference to Arbitrary Quiz Question/Answer Modification and Deletion via 'payload' Parameter

Medium 4.3

In plain English

A medium-severity authorization bypass via user-controlled key in Tutor LMS – eLearning and online course solution from themeum. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 38% of all known vulnerabilities).

Severity (CVSS 3.1)4.3Medium

Exploit odds (30 days)0.4%top 62.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
themeum	Tutor LMS – eLearning and online course solution	0 – through 4.0.7

Weakness: CWE-639 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

In plain English

Official description

Affected products (as reported)

References