Heap-based buffer overflow in the Recovery Mode component in Apple iPhone OS before 3.1, and iPhone OS before 3.1.1 for iPod touch, allows local users to bypass the passcode requirement and access arbitrary data via vectors related to "command parsing."
https://exchange.xforce.ibmcloud.com/vulnerabilities/53183
http://www.securityfocus.com/bid/36341
http://support.apple.com/kb/HT3860
http://secunia.com/advisories/36677
http://lists.apple.com/archives/security-announce/2009/Sep/msg00001.html