Siemens C450 IP and C475 IP VoIP devices allow remote attackers to cause a denial of service (disconnected calls and device reboot) via a crafted SIP packet to UDP port 5060.
https://www.exploit-db.com/exploits/7220
https://exchange.xforce.ibmcloud.com/vulnerabilities/46820
http://www.securityfocus.com/archive/1/498599/100/0/threaded