The Media Library Assistant plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'search-string' parameter in all versions up to, and including, 3.42 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. Exploitation requires the targeted site to have a publicly accessible page containing an [mla_gallery] shortcode configured with a pagination output mode and an mla_link_href template that reflects a {+request:...+} token, along with enough attachments to trigger pagination.