The Master Slider – Responsive Touch Slider plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugins ms_slide_info shortcode in all versions up to, and including, 3.9.9 due to insufficient input sanitization and output escaping on user supplied tag_name attribute. 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.