The SEO Backlinks WordPress plugin is vulnerable to Cross-Site Request Forgery via the loc_config function found in the ~/seo-backlinks.php file which allows attackers to inject arbitrary web scripts, in versions up to and including 4.0.1.
https://www.wordfence.com/vulnerability-advisories/#CVE-2021-34632
https://plugins.trac.wordpress.org/browser/seo-backlinks/trunk/seo-backlinks.php#L75