CSPOC in IBM PowerHA SystemMirror on AIX 6.1 and 7.1 allows remote authenticated users to perform an "su root" action by leveraging presence on the cluster-wide password-change list.
http://aix.software.ibm.com/aix/efixes/security/powerha_advisory.asc
http://www-01.ibm.com/support/docview.wss?uid=isg1IV76943