The Client Testimonial Slider plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'aft_testimonial_meta_name' custom field in the Client Information metabox in all versions up to, and including, 2.0 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 the injected administrative page.