The sock_alloc_send_pskb function in net/core/sock.c in the Linux kernel
before 3.4.5 does not properly validate a certain length value, which
allows local users to cause a denial of service (heap-based buffer overflow
and system crash) or possibly gain privileges by leveraging access to a
TUN/TAP device.

An error was discovered in the Linux kernel's network TUN/TAP device
implementation. A local user with access to the TUN/TAP interface (which is
not available to unprivileged users until granted by a root user) could
exploit this flaw to crash the system or potential gain administrative
privileges.