Deactivate and delete. The vulnerability was reported to the WordPress plugins team on Jan 18, 2023.
István Márton discovered and reported this Cross Site Scripting (XSS) vulnerability in WordPress Ultimate WP Query Search Filter Plugin. This could allow a malicious actor to inject malicious scripts, such as redirects, advertisements, and other HTML payloads into your website which will be executed when guests visit your site. This vulnerability has not been known to be fixed yet.