(RHSA-2007:0323) Important: xen security update

The Xen package contains the tools for managing the virtual machine monitor
in Red Hat Enterprise Linux virtualization.

The following security flaws are fixed in the updated Xen package:

Joris van Rantwijk found a flaw in the Pygrub utility which is used as a
boot loader for guest domains. A malicious local administrator of a guest
domain could create a carefully crafted grub.conf file which would trigger
the execution of arbitrary code outside of that domain. (CVE-2007-4993)

Tavis Ormandy discovered a heap overflow flaw during video-to-video copy
operations in the Cirrus VGA extension code used in Xen. A malicious local
administrator of a guest domain could potentially trigger this flaw and
execute arbitrary code outside of the domain. (CVE-2007-1320)

Tavis Ormandy discovered insufficient input validation leading to a heap
overflow in the Xen NE2000 network driver. If the driver is in use, a
malicious local administrator of a guest domain could potentially trigger
this flaw and execute arbitrary code outside of the domain. Xen does not
use this driver by default. (CVE-2007-1321)

Users of Xen should update to these erratum packages containing backported
patches which correct these issues.