The Research in Motion BlackBerry 7270 with 4.0 SP1 Bundle 83 allows remote attackers to cause a denial of service (blocked call reception) via a malformed SIP invite message, possibly related to multiple format string specifiers in the From field, a spoofed source IP address, and limitations of the function stack frame.
https://exchange.xforce.ibmcloud.com/vulnerabilities/35074
http://www.sipera.com/index.php?action=resources%2Cthreat_advisory&tid=211&
http://www.securityfocus.com/bid/24548
http://www.kb.cert.org/vuls/id/785257
http://www.blackberry.com/btsc/articles/225/KB12700_f.SAL_Public.html