The s2Member plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and…

Why it is Amber

• CVSS 9.8 critical
• Remotely exploitable without logging in

References

• https://plugins.trac.wordpress.org/browser/s2member/tags/260829/src/includes/classes/paypal-notify-in-subscr-or-wa-w-level.inc.php#L514
• https://plugins.trac.wordpress.org/browser/s2member/tags/260829/src/includes/classes/paypal-notify-in-web-accept-sp.inc.php#L104
• https://plugins.trac.wordpress.org/browser/s2member/tags/260829/src/includes/classes/paypal-notify-in-web-accept-sp.inc.php#L131
• https://plugins.trac.wordpress.org/browser/s2member/tags/260829/src/includes/classes/paypal-notify-in-web-accept-sp.inc.php#L138
• https://plugins.trac.wordpress.org/browser/s2member/tags/260829/src/includes/classes/paypal-notify-in.inc.php#L49
• https://plugins.trac.wordpress.org/browser/s2member/tags/260829/src/includes/classes/utilities.inc.php#L49
• https://plugins.trac.wordpress.org/browser/s2member/tags/260829/src/includes/classes/utils-strings.inc.php#L201
• https://plugins.trac.wordpress.org/changeset/3722434/s2member
• https://www.wordfence.com/threat-intel/vulnerabilities/id/bbe64cd3-c5ca-4867-90de-4784510a1126?source=cve

Original description

The s2Member plugin for WordPress is vulnerable to Remote Code Execution in all versions up to, and including, <= 260927 via the 'item_name' parameter parameter. This is due to insufficient sanitization in strip_php_tags_deep(), which only strips literal '<?' sequences, combined with a post-interpolation placeholder cleanup that reassembles a valid '<?php' opener after the attacker-controlled value has already been embedded in the email template. This makes it possible for authenticated attackers, with custom-level access and above, to execute code on the server.