In the Elementor Website Builder WordPress plugin before 3.1.4, the image box widget (includes/widgets/image-box.php) accepts a ??title_size?? parameter. Although the element control lists a fixed set of possible html tags, it is possible for a user with Contributor or above permissions to send a modified ??save_builder?? request containing JavaScript in the ??title_size?? parameter, which is not filtered and is output without escaping. This JavaScript will then be executed when the saved page is viewed or previewed.
