CVE-2026-18439: Software Security Vulnerability Vulnerability
MODERATECVE-2026-18439 is a MODERATE (CVSS 4.3) security vulnerability vulnerability (CWE-639: Authorization Bypass Through User-Controlled Key) affecting Software libraries in the Maven ecosystem. The weakness occurs when the system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.. Remediation is available in the latest vendor maintenance releases.
CVE-2026-18439 at a Glance
Security Impact
CVSS: 4.3
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N).
How to Fix CVE-2026-18439
To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Run the following command in your project directory to verify that all resolved dependencies use the patched release:
mvn dependency:treeHow to Check if You Are Affected
To determine whether your Java application is affected by CVE-2026-18439, inspect your build dependencies using the Maven Dependency Plugin:
mvn dependency:treeAnalyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.
Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-639: Authorization Bypass Through User-Controlled Key, where the system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
References
Frequently Asked Questions
What is CVE-2026-18439?
Which Software versions are affected?
What version fixes CVE-2026-18439?
What is the CVSS score of CVE-2026-18439?
What CWE is associated with CVE-2026-18439?
How can I check Maven dependencies for CVE-2026-18439?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-9x9f-f428-ff8p",
"modified" : "2026-09-22T09:31:12Z",
"published" : "2026-09-22T09:31:12Z",
"aliases" : [ "CVE-2026-18439" ],
"details" : "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.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N"
} ],
"affected" : [ ],
"references" : [ {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-18439"
}, {
"type" : "WEB",
"url" : "https://plugins.trac.wordpress.org/browser/tutor/tags/3.9.10/classes/QuizBuilder.php#L156"
}, {
"type" : "WEB",
"url" : "https://plugins.trac.wordpress.org/browser/tutor/tags/3.9.10/classes/QuizBuilder.php#L291"
}, {
"type" : "WEB",
"url" : "https://plugins.trac.wordpress.org/browser/tutor/tags/3.9.10/classes/QuizBuilder.php#L423"
}, {
"type" : "WEB",
"url" : "https://plugins.trac.wordpress.org/browser/tutor/tags/3.9.10/classes/QuizBuilder.php#L430"
}, {
"type" : "WEB",
"url" : "https://plugins.trac.wordpress.org/browser/tutor/tags/3.9.10/classes/QuizBuilder.php#L781"
}, {
"type" : "WEB",
"url" : "https://plugins.trac.wordpress.org/browser/tutor/tags/4.0.3/classes/QuizBuilder.php#L156"
}, {
"type" : "WEB",
"url" : "https://plugins.trac.wordpress.org/browser/tutor/tags/4.0.3/classes/QuizBuilder.php#L291"
}, {
"type" : "WEB",
"url" : "https://plugins.trac.wordpress.org/browser/tutor/tags/4.0.3/classes/QuizBuilder.php#L423"
}, {
"type" : "WEB",
"url" : "https://plugins.trac.wordpress.org/browser/tutor/tags/4.0.3/classes/QuizBuilder.php#L430"
}, {
"type" : "WEB",
"url" : "https://plugins.trac.wordpress.org/browser/tutor/tags/4.0.3/classes/QuizBuilder.php#L781"
}, {
"type" : "WEB",
"url" : "https://plugins.trac.wordpress.org/changeset/3690454/tutor/tags/4.0.8/classes/QuizBuilder.php"
}, {
"type" : "WEB",
"url" : "https://www.wordfence.com/threat-intel/vulnerabilities/id/6d07c82d-262a-4ac1-9ee5-7ef4d025f66f?source=cve"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-639" ],
"severity" : "MODERATE",
"github_reviewed" : false,
"github_reviewed_at" : null,
"nvd_published_at" : "2026-09-22T08:16:39Z"
}
}