The activation resend function in the Profiles module in XOOPS before 2.4.1 sends activation codes in response to arbitrary activation requests, which allows remote attackers to bypass administrative approval via a request involving activate.php.
http://www.xoops.org/modules/news/article.php?storyid=5096
http://www.xoops.org/modules/newbb/viewtopic.php?post_id=319132