From $URL :
Linux kernel built with XFRM framework support is vulnerable to a NULL pointer
dereference flaw. It occurs while accessing XFRM state via xfrm_state_netlink
A privileged(CAP_NET_ADMIN) user/program could use this flaw to crash systems,
resulting in DoS.
There are no longer any 2.x or <3.5.7 kernels available in the repository with
the exception of sys-kernel/xbox-sources which is unsupported by security.