Provide references for CVE-2021-38351.
Where can I find more information about CVE-2021-38351?
References are available at: https://www.wordfence.com/vulnerability-advisories/#CVE-2021-38351, https://plugins.trac.wordpress.org/browser/osd-subscribe/tags/1.2.3/options/osd_subscribe_options_subscribers.php#L86.