Cisco PIX 500 and ASA 5500 Series Security Appliances 6.x before 6.3(5.115), 7.0 before 7.0(5.2), and 7.1 before 7.1(2.5), and the FWSM 3.x before 3.1(3.24), when the "inspect sip" option is enabled, allows remote attackers to cause a denial of service (device reboot) via malformed SIP packets.