The Animate Your Content plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's 'animation-set' shortcode in versions up to, and including, 1.0.0. This is due to insufficient input sanitization and output escaping on user supplied attributes in the shortcode_args_to_html_attrs() function, which concatenates shortcode attribute values directly into double-quoted HTML attributes without calling esc_attr(). 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.