What the vulnerability does
01Description
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 do_shortcode() on user-submitted quiz answer text. User-submitted answers pass through sanitize_text_field() and htmlspecialchars(), which only strip HTML tags but do not encode or remove shortcode brackets [ and ]. When quiz results are displayed, the plugin calls do_shortcode() 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 [qsm_result id=X] to access other users' quiz submissions without authorization, as the qsm_result shortcode lacks any authorization checks.
