The Masteriyo LMS – Online Course Builder for eLearning, LMS & Education plugin for WordPress is vulnerable to Authorization Bypass Through User-Controlled Key in versions up to and including 2.1.7. This is due to insufficient webhook signature verification in the handle_webhook() function. The webhook endpoint processes unauthenticated requests and only performs signature verification if both the webhook_secret setting is configured AND the HTTP_STRIPE_SIGNATURE header is present. Since webhook_secret defaults to an empty string, the webhook processes attacker-controlled JSON payloads without any verification. This makes it possible for unauthenticated attackers to send fake Stripe webhook events with arbitrary order_id values in the metadata, mark any order as completed without payment, and gain unauthorized access to paid course content.

The Masteriyo LMS plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 2.1.6. This is due to the plugin allowing a user to update the user role through the 'InstructorsController::prepare_object_for_database' function. This makes it possible for authenticated attackers, with Student-level access and above, to elevate their privileges to that of an administrator.

The Masteriyo LMS – eLearning and Online Course Builder for WordPress plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the question's content parameter in all versions up to, and including, 1.13.3 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with student-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.

The Masteriyo LMS – eLearning and Online Course Builder for WordPress plugin for WordPress is vulnerable to unauthorized user profile modification due to missing authorization checks on the /wp-json/masteriyo/v1/users/$id REST API endpoint in all versions up to, and including, 1.13.3. This makes it possible for authenticated attackers, with student-level access and above, to modify the roles of arbitrary users. As a result, attackers can escalate their privileges to the Administrator and demote existing administrators to students.