Double free vulnerability in the xfrm6_tunnel_rcv function in net/ipv6/xfrm6_tunnel.c in the Linux kernel before 2.6.22, when the xfrm6_tunnel module is enabled, allows remote attackers to cause a denial of service (panic) via crafted IPv6 packets.
http://marc.info/?l=bugtraq&m=133951357207000&w=2
http://rhn.redhat.com/errata/RHSA-2012-0488.html
https://bugzilla.redhat.com/show_bug.cgi?id=752304
http://secunia.com/advisories/48881
https://github.com/torvalds/linux/commit/d0772b70faaf8e9f2013b6c4273d94d5eac8047a