The __inet6_check_established function in net/ipv6/inet6_hashtables.c in the Linux kernel before 2.6.29, when Network Namespace Support (aka NET_NS) is enabled, allows remote attackers to cause a denial of service (NULL pointer dereference and system crash) via vectors involving IPv6 packets.
http://www.ubuntu.com/usn/usn-793-1
http://www.securityfocus.com/bid/34602
http://www.mandriva.com/security/advisories?name=MDVSA-2009:135
http://www.kernel.org/pub/linux/kernel/v2.6/ChangeLog-2.6.29
http://secunia.com/advisories/35656
http://secunia.com/advisories/35387
http://lists.opensuse.org/opensuse-security-announce/2009-06/msg00002.html