WebLibrarian <= 3.5.8.1 - Reflected Cross-Site Scripting via multiple parameters

The WebLibrarian plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via multiple parameters in versions up to, and including, 3.5.8.1 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link. Note that although a patch was released in 3.5.8.2, the plugin is still theoretically vulnerable due to the use of 'sanitize_text_field' but since the vulnerable parameters are echoed in hidden elements, exploitation is impractical.