The SIP implementation in Cisco Unified Communications Manager (CUCM) 6.x and 7.x before 7.1(5b)su5, 8.x before 8.5(1)su4, and 8.6 before 8.6(2a)su1; Cisco IOS 12.2 through 12.4 and 15.0 through 15.2; and Cisco IOS XE 3.3.xSG before 3.3.1SG, 3.4.xS, and 3.5.xS allows remote attackers to cause a denial of service (service crash or device reload) via a crafted SIP message containing an SDP session description, aka Bug IDs CSCtw66721, CSCtj33003, and CSCtw84664.