formmail.php in Jetbox CMS 2.1 allows remote attackers to send arbitrary e-mails (spam) via modified recipient, _SETTINGS[allowed_email_hosts][], and subject parameters.
https://exchange.xforce.ibmcloud.com/vulnerabilities/34292
http://www.vupen.com/english/advisories/2007/1831
http://www.securitytracker.com/id?1018063
http://www.securityfocus.com/bid/23989
http://www.securityfocus.com/archive/1/468644/100/0/threaded