The WP SEO Tags WordPress plugin is vulnerable to Reflected Cross-Site Scripting via the saq_txt_the_filter parameter in the ~/wp-seo-tags.php file which allows attackers to inject arbitrary web scripts, in versions up to and including 2.2.7.
https://www.wordfence.com/vulnerability-advisories/#CVE-2021-34665
https://plugins.trac.wordpress.org/browser/wp-seo-tags/trunk/wp-seo-tags.php#L378