The Simple Responsive Slider plugin for WordPress is vulnerable to Stored Cross-Site Scripting in all versions up to, and including, 2.0 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.
https://wordpress.org/plugins/addi-simple-slider/#developers
https://plugins.svn.wordpress.org/addi-simple-slider/tags/2.0/methods.php