The SiteOrigin Widgets Bundle plugin for WordPress is vulnerable to unauthorized arbitrary shortcode execution in all versions up to, and including, 1.70.4. This is due to a missing capability check on the siteorigin_widget_preview_widget_action() function which is registered via the wp_ajax_so_widgets_preview AJAX action. The function only verifies a nonce (widgets_action) but does not check user capabilities. This makes it possible for authenticated attackers, with Subscriber-level access and above, to execute arbitrary shortcodes by invoking the SiteOrigin_Widget_Editor_Widget via the preview endpoint. The required nonce is exposed on the public frontend when the Post Carousel widget is present on a page, embedded in the data-ajax-url HTML attribute.