The Quiz and Survey Master (QSM) – Easy Quiz and Survey Maker plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'question_title' parameter in all versions up to, and including, 11.2.1 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
https://plugins.trac.wordpress.org/browser/quiz-master-next/tags/11.1.4/php/rest-api.php#L741
https://plugins.trac.wordpress.org/browser/quiz-master-next/tags/11.1.4/php/rest-api.php#L301
https://plugins.trac.wordpress.org/browser/quiz-master-next/tags/11.0.0/php/rest-api.php#L741
https://plugins.trac.wordpress.org/browser/quiz-master-next/tags/11.0.0/php/rest-api.php#L301