Integer overflow in FreeBSD before 8.4 p24, 9.x before 9.3 p10. 10.0 before p18, and 10.1 before p6 allows remote attackers to cause a denial of service (crash) via a crafted IGMP packet, which triggers an incorrect size calculation and allocation of insufficient memory.
https://www.pfsense.org/security/advisories/pfSense-SA-15_02.igmp.asc
https://www.freebsd.org/security/advisories/FreeBSD-SA-15:04.igmp.asc
https://kc.mcafee.com/corporate/index?page=content&id=SB10107
http://www.securitytracker.com/id/1031798