Red Hat 6: RHSA-2013:1272-01 Important: Libvirt Security Flaw

The libvirt library is a C API for managing and interacting with the virtualization capabilities of Linux and other operating systems. In addition, libvirt provides tools for remote management of virtualized systems.
libvirt invokes the PolicyKit pkcheck utility to handle authorization. A race condition was found in the way libvirt used this utility, allowing a local user to bypass intended PolicyKit authorizations or execute arbitrary commands with root privileges. (CVE-2013-4311)
Note: With this update, libvirt has been rebuilt to communicate with PolicyKit via a different API that is not vulnerable to the race condition. The polkit RHSA-2013:1270 advisory must also be installed to fix the CVE-2013-4311 issue.
An invalid free flaw was found in libvirtd's remoteDispatchDomainMemoryStats function. An attacker able to establish a read-only connection to libvirtd could use this flaw to crash libvirtd. (CVE-2013-4296)
The CVE-2013-4296 issue was discovered by Daniel P. Berrange of Red Hat.
This update also fixes the following bugs:
* Prior to this update, the libvirtd daemon leaked memory in the virCgroupMoveTask() function. A fix has been provided which prevents libvirtd from incorrect management of memory allocations. (BZ#984556)
* Previously, the libvirtd daemon was accessing one byte before the array in the virCgroupGetValueStr() function. This bug has been fixed and libvirtd now stays within the array bounds. (BZ#984561)
* When migrating, libvirtd leaked the migration URI (Uniform Resource Identifier) on destination. A patch has been provided to fix this bug and the migration URI is now freed correctly. (BZ#984578)
* Updating a network interface using virDomainUpdateDeviceFlags API failed when a boot order was set for that interface. The update failed even if the boot order was set in the provided device XML. The virDomainUpdateDeviceFlags API has been fixed to correctly parse the boot order specification from the provided device XML and updating network interfaces with boot orders now works as expected. (BZ#1003934)
Users of libvirt are advised to upgrade to these updated packages, which contain backported patches to correct these issues. After installing the updated packages, libvirtd will be restarted automatically.