Memory leak in the unshare_userns function in kernel/user_namespace.c in the Linux kernel before 3.10.6 allows local users to cause a denial of service (memory consumption) via an invalid CLONE_NEWUSER unshare call.
http://www.ubuntu.com/usn/USN-1974-1
http://www.ubuntu.com/usn/USN-1971-1
http://www.openwall.com/lists/oss-security/2013/08/06/2
http://www.kernel.org/pub/linux/kernel/v3.x/ChangeLog-3.10.6