Buffer overflow in setsenv command in IBM AIX 4.3.x and earlier allows local users to execute arbitrary commands via a long "x=" argument.
https://exchange.xforce.ibmcloud.com/vulnerabilities/5621
http://www.securityfocus.com/bid/2032
http://www-1.ibm.com/support/search.wss?rs=0&q=IY10721&apar=only
http://www-1.ibm.com/support/search.wss?rs=0&q=IY08812&apar=only