CVE-2013-1766 (http://nvd.nist.gov/nvd.cfm?cvename=CVE-2013-1766): libvirt 1.0.2 and earlier sets the group owner to kvm for device files, which allows local users to write to these files via unspecified vectors.
I didn't file this bug because after talk with Cardoe on irc, it seems to be invalid on gentoo. Here the vms are owned by qemu:qemu
This isn't an upstream bug but a Debian specific bug since they tried to save on creating an extra group and instead shared a group.
(In reply to comment #2) > This isn't an upstream bug but a Debian specific bug since they tried to > save on creating an extra group and instead shared a group. Thanks for the info, Doug.