The executable comment feature in MySQL 5.0.x before 5.0.93 and 5.1.x before 5.1.50, when running in certain slave configurations in which the slave is running a newer version than the master, allows remote attackers to execute arbitrary SQL commands via custom comments.
http://bugs.mysql.com/bug.php?id=49124
http://dev.mysql.com/doc/refman/5.0/en/news-5-0-93.html
http://dev.mysql.com/doc/refman/5.1/en/news-5-1-50.html
http://lists.opensuse.org/opensuse-security-announce/2012-08/msg00007.html
http://seclists.org/oss-sec/2011/q4/101