Description
Joomla! Core is prone to a spam vulnerability. Exploiting this issue may allow attackers to send spam through the affected website. Joomla! Core version 1.6.0 is vulnerable.
Remediation
Update to Joomla! Core version 1.6.1 or latest
References
http://joomlacode.org/gf/project/joomla/tracker/?action=TrackerItemEdit&tracker_item_id=24288
https://www.exploit-db.com/exploits/15979/
https://www.joomla.org/announcements/release-news/5350-joomla-161-released.html