Mantis before 20041016 provides a complete Issue History (Bug History) in the web interface regardless of view_history_threshold, which allows remote attackers to obtain sensitive information (private bug details) by visiting a bug's web page.
http://mantisbt.cvs.sourceforge.net/mantisbt/mantisbt/history_inc.php?view=log
http://mantisbt.cvs.sourceforge.net/mantisbt/mantisbt/history_inc.php?r1=1.24&r2=1.25