Mantis 1.0.0rc3 and earlier discloses private bugs via public RSS feeds, which allows remote attackers to obtain sensitive information.
http://www.vupen.com/english/advisories/2005/3064
http://www.debian.org/security/2005/dsa-944
http://sourceforge.net/project/shownotes.php?release_id=377934&group_id=14963
http://secunia.com/advisories/18481