ip6_tables in netfilter in the Linux kernel before 2.6.16.31 allows remote attackers to (1) bypass a rule that disallows a protocol, via a packet with the protocol header not located immediately after the fragment header, aka "ip6_tables protocol bypass bug;" and (2) bypass a rule that looks for a certain extension header, via a packet with an extension header outside the first fragment, aka "ip6_tables extension header bypass bug."
http://www.vupen.com/english/advisories/2006/4386
http://www.ubuntu.com/usn/usn-416-1
http://www.ubuntu.com/usn/usn-395-1
http://www.securityfocus.com/bid/20955
http://www.securityfocus.com/archive/1/471457
http://www.novell.com/linux/security/advisories/2006_79_kernel.html
http://www.mandriva.com/security/advisories?name=MDKSA-2006:197
http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.16.31
http://secunia.com/advisories/25691
http://secunia.com/advisories/24098
http://secunia.com/advisories/23474
http://secunia.com/advisories/23384
http://secunia.com/advisories/22762
http://secunia.com/advisories/22731
http://readlist.com/lists/vger.kernel.org/linux-kernel/55/275979.html