Unspecified vulnerability in the SIP channel driver (channels/chan_sip.c) in Asterisk 1.2.x before 1.2.13 and 1.4.x before 1.4.0-beta3 allows remote attackers to cause a denial of service (resource consumption) via unspecified vectors that result in the creation of "a real pvt structure" that uses more resources than necessary.
https://exchange.xforce.ibmcloud.com/vulnerabilities/29664
http://www.vupen.com/english/advisories/2006/4098
http://www.securityfocus.com/bid/20835
http://www.securityfocus.com/archive/1/449183/100/0/threaded
http://www.novell.com/linux/security/advisories/2006_69_asterisk.html
http://www.gentoo.org/security/en/glsa/glsa-200610-15.xml
http://www.asterisk.org/node/110
http://www.asterisk.org/node/109
http://secunia.com/advisories/22979
http://secunia.com/advisories/22651
http://ftp.digium.com/pub/asterisk/releases/ChangeLog-1.2.13