WP Airbnb Review Slider <= 4.2 - Authenticated (Admin+) Stored Cross-Site Scripting

The WP Airbnb Review Slider plugin for WordPress is vulnerable to Stored Cross-Site Scripting via admin settings in all versions up to, and including, 4.2 due to insufficient URL validation that allows users to pull in a malicious HTML file. This makes it possible for authenticated attackers, with administrator-level permissions and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This only affects multi-site installations and installations where unfiltered_html has been disabled.