Bold Page Builder <= 5.7.2 - Authenticated (Contributor+) Stored Cross-Site Scripting via 'background_image' Parameter

The Bold Page Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'background_image' parameter of the plugin's bt_bb_section shortcode in all versions up to, and including, 5.7.2 due to insufficient input sanitization and output escaping on user-supplied attributes. 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.