Red Hat: RHSA-2011:0391 Critical: libvirt Limited Access Vulnerability

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 remotely managing virtualized systems.
It was found that several libvirt API calls did not honor the read-only permission for connections. A local attacker able to establish a read-only connection to libvirtd on a server could use this flaw to execute commands that should be restricted to read-write connections, possibly leading to a denial of service or privilege escalation. (CVE-2011-1146)
Note: Previously, using rpmbuild without the '--define "rhel 5"' option to build the libvirt source RPM on Red Hat Enterprise Linux 5 failed with a "Failed build dependencies" error for the device-mapper-devel package, as this -devel sub-package is not available on Red Hat Enterprise Linux 5. With this update, the -devel sub-package is no longer checked by default as a dependency when building on Red Hat Enterprise Linux 5, allowing the libvirt source RPM to build as expected.
All libvirt users are advised to upgrade to these updated packages, which contain a backported patch to resolve this issue. After installing the updated packages, libvirtd must be restarted ("service libvirtd restart") for this update to take effect.