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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-18439
StatePUBLISHED
AssignerWordfence
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-22 08:16:39 UTC
Updated2026-09-23 19:17:29 UTC
DescriptionThe 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.

Risk And Classification

Primary CVSS: v3.1 4.3 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

EPSS: 0.002500000 probability, percentile 0.145130000 (date 2026-09-24)

Problem Types: CWE-639 | CWE-639 CWE-639 Authorization Bypass Through User-Controlled Key

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary4.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
3.1CNADECLARED4.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Themeum Tutor LMS ELearning And Online Course Solution affected 4.0.7 semver Not specified

References

ReferenceSourceLinkTags
plugins.trac.wordpress.org/browser/tutor/tags/3.9.10/classes/QuizBuilder.php [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/tutor/tags/3.9.10/classes/QuizBuilder.php [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/tutor/tags/3.9.10/classes/QuizBuilder.php [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/tutor/tags/4.0.3/classes/QuizBuilder.php [email protected] plugins.trac.wordpress.org
www.wordfence.com/threat-intel/vulnerabilities/id/6d07c82d-262a-4ac1-9ee5-7ef4d... [email protected] www.wordfence.com
plugins.trac.wordpress.org/browser/tutor/tags/4.0.3/classes/QuizBuilder.php [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/tutor/tags/3.9.10/classes/QuizBuilder.php [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/tutor/tags/3.9.10/classes/QuizBuilder.php [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/tutor/tags/4.0.3/classes/QuizBuilder.php [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/changeset/3690454/tutor/tags/4.0.8/classes/QuizBuilder.php [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/tutor/tags/4.0.3/classes/QuizBuilder.php [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/tutor/tags/4.0.3/classes/QuizBuilder.php [email protected] plugins.trac.wordpress.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Nakul Chodha (en)

Additional Advisory Data

SourceTimeEvent
CNA2026-07-30T20:38:30.000ZVendor Notified
CNA2026-09-21T18:52:22.000ZDisclosed

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