Cisco IOS 15.3M before 15.3(3)M2 and IOS XE 3.10.xS before 3.10.2S allow remote attackers to cause a denial of service (device reload) via crafted SIP messages, aka Bug ID CSCug45898.
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20140326-sip