The Open Phone Abstraction Library (opal), as used by (1) Ekiga before 2.0.10 and (2) OpenH323 before 2.2.4, allows remote attackers to cause a denial of service (crash) via an invalid Content-Length header field in Session Initiation Protocol (SIP) packets, which causes a \0 byte to be written to an "attacker-controlled address."
https://www.exploit-db.com/exploits/9240
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A11398
https://bugzilla.redhat.com/show_bug.cgi?id=296371
http://www.vupen.com/english/advisories/2007/3414
http://www.vupen.com/english/advisories/2007/3413
http://www.ubuntu.com/usn/usn-562-1
http://www.securitytracker.com/id?1018776
http://www.securityfocus.com/bid/25955
http://www.securityfocus.com/archive/1/482120/30/4500/threaded
http://www.s21sec.com/avisos/s21sec-037-en.txt
http://www.redhat.com/support/errata/RHSA-2007-0957.html
http://www.mandriva.com/security/advisories?name=MDKSA-2007:205
http://secunia.com/advisories/28380
http://secunia.com/advisories/27524
http://secunia.com/advisories/27271
http://secunia.com/advisories/27129
http://secunia.com/advisories/27128
http://secunia.com/advisories/27118
http://openh323.cvs.sourceforge.net/openh323/opal/src/sip/sippdu.cxx?r1=2.83.2.19&r2=2.83.2.20
http://mail.gnome.org/archives/ekiga-list/2007-September/msg00103.html
http://lists.opensuse.org/opensuse-security-announce/2007-10/msg00006.html