Recovery Mode in Apple iPhone OS 1.0 through 3.1.2, and iPhone OS for iPod touch 1.1 through 3.1.2, allows physically proximate attackers to bypass device locking, and read or modify arbitrary data, via a USB control message that triggers memory corruption.
http://www.securityfocus.com/bid/38040
http://support.apple.com/kb/HT4013
http://lists.apple.com/archives/security-announce/2010/Feb/msg00000.html