The Optio Dentistry plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's 'optio-lightbox' shortcode in all versions up to, and including, 2.1 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.
https://plugins.trac.wordpress.org/browser/optio-dentistry/tags/2.1/optio-dentistry.php#L92
https://plugins.trac.wordpress.org/browser/optio-dentistry/tags/2.1/optio-dentistry.php#L18