The LearnPress plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'class_wrapper_form' shortcode attribute in versions up to, and including, 4.4.0. This is due to insufficient input sanitization and output escaping in the FilterCourseTemplate::sections() method at line 98, where the attacker-controlled attribute is inserted into an HTML class attribute via sprintf('<form class="%s">', $class_wrapper_form) without esc_attr() escaping. The FilterCourseShortcode::render() handler does not apply shortcode_atts() filtering, so raw user attributes flow directly through do_action('learn-press/filter-courses/layout', $data) into the template. 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.