Quick answers
- Is CVE-2026-18439 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-18439 being exploited in the wild.
- How severe is CVE-2026-18439?
- Medium severity, with a CVSS score of 4.3, published 22 September 2026.
- Which products and versions are affected?
- Themeum Tutor LMS up to and including 4.0.7.
- Is there a fix for CVE-2026-18439?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-18439 attacked?
- It is attacked over the network, in a web application.
- Am I affected by CVE-2026-18439?
- Check whether you run Themeum Tutor LMS at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The vulnerability is an insecure direct object reference (IDOR) in the tutor_quiz_builder_save AJAX action, where the handler validates top-level course_id and topic_id but passes nested question_id, answer_id, deleted_question_ids[], and deleted_answer_ids[] directly into database update and delete operations without verifying ownership. An authenticated attacker with Instructor-level access can craft requests to overwrite quiz questions and answers belonging to other instructors, or delete arbitrary question and answer records via QuizBuilder::save_questions(), QuizBuilder::save_question_answers(), and QuizBuilder::handle_delete() functions.
Affected products
- Themeum Tutor LMS up to and including 4.0.7
Timeline
- 2026-09-22: disclosed