The Quiz and Survey Master (QSM) – Quiz Maker & Survey Maker plugin for WordPress is vulnerable to Stored DOM-Based Cross-Site Scripting via the 'qsmhiddenquestions' parameter in all versions up to, and including, 11.2.6 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This requires the attacker to force the mlwresults INSERT to fail by submitting an over-length or duplicate qsmuniquekey value, which triggers the audit trail code branch that writes the unescaped payload to wpmlwqmaudittrail.formdata.

The Quiz And Survey Master plugin for WordPress is vulnerable to Arbitrary Shortcode Execution in versions up to and including 11.1.0. This is due to insufficient input sanitization and the execution of doshortcode() on user-submitted quiz answer text. User-submitted answers pass through sanitizetextfield() and htmlspecialchars(), which only strip HTML tags but do not encode or remove shortcode brackets [ and ]. When quiz results are displayed, the plugin calls doshortcode() on the entire results page output (including user answers), causing any injected shortcodes to be executed. This makes it possible for unauthenticated attackers to inject arbitrary WordPress shortcodes such as [qsmresult id=X] to access other users' quiz submissions without authorization, as the qsmresult shortcode lacks any authorization checks.

The Quiz and Survey Master (QSM) WordPress plugin before 9.0.2 does not validate and escape some of its Quiz fields before outputting them back in a page/post where the Quiz is embed, which could allow users with the contributor role and above to perform Stored Cross-Site Scripting attacks