The Session Initiation Protocol (SIP) implementation in multiple Cisco products including IP Phone models 7940 and 7960, IOS versions in the 12.2 train, and Secure PIX 5.2.9 to 6.2.2 allows remote attackers to cause a denial of service and possibly execute arbitrary code via crafted INVITE messages, as demonstrated by the OUSPG PROTOS c07-sip test suite.
www.cert.org/advisories/CA-2003-06.html
www.cisco.com/warp/public/707/cisco-sa-20030221-protos.shtml
www.ee.oulu.fi/research/ouspg/protos/testing/c07/sip/
www.kb.cert.org/vuls/id/528719
www.securityfocus.com/bid/6904
www.securitytracker.com/id?1006143
www.securitytracker.com/id?1006144
www.securitytracker.com/id?1006145
exchange.xforce.ibmcloud.com/vulnerabilities/11379