A certain Debian patch to the IPv6 implementation in the Linux kernel 3.2.x through 3.2.63 does not properly validate arguments in ipv6_select_ident function calls, which allows local users to cause a denial of service (NULL pointer dereference and system crash) by leveraging (1) tun or (2) macvtap device access.
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=766195
http://www.ubuntu.com/usn/USN-2418-1
http://www.ubuntu.com/usn/USN-2417-1
http://www.securityfocus.com/bid/70867