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.