The Oboxmedia Ads plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'before_widget' and 'after_widget' parameters of the oboxads-ad-widget shortcode in all versions up to, and including, 1.9.8. This is due to insufficient input sanitization and output escaping. 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.