sys/netinet6/icmp6.c in the kernel in FreeBSD 6.3 through 7.1, NetBSD 3.0 through 4.0, and possibly other operating systems does not properly check the proposed new MTU in an ICMPv6 Packet Too Big Message, which allows remote attackers to cause a denial of service (panic) via a crafted Packet Too Big Message.
https://exchange.xforce.ibmcloud.com/vulnerabilities/44908
http://www.vupen.com/english/advisories/2009/1297
http://www.vupen.com/english/advisories/2009/0633
http://www.us-cert.gov/cas/techalerts/TA09-133A.html
http://www.securitytracker.com/id?1021111
http://www.securitytracker.com/id?1020820
http://www.securityfocus.com/bid/31004
http://support.apple.com/kb/HT3549
http://support.apple.com/kb/HT3467
http://security.freebsd.org/advisories/FreeBSD-SA-08:09.icmp6.asc
http://secunia.com/advisories/35074
http://secunia.com/advisories/32401
http://secunia.com/advisories/31745
http://lists.apple.com/archives/security-announce/2009/May/msg00002.html