The Mail component in Apple iPhone OS 1.0 through 2.2.1 and iPhone OS for iPod touch 1.1 through 2.2.1 dismisses the call approval dialog when another alert appears, which might allow remote attackers to force the iPhone to place a call without user approval by causing an application to trigger an alert.
https://exchange.xforce.ibmcloud.com/vulnerabilities/51210
http://www.vupen.com/english/advisories/2009/1621
http://www.securityfocus.com/bid/35414
http://support.apple.com/kb/HT3639
http://lists.apple.com/archives/security-announce/2009/Jun/msg00005.html