It was discovered that libvirt would probe disk backing stores without consulting the defined format for the disk. A privileged attacker in the guest could exploit this to read arbitrary files on the host. This issue only affected Ubuntu 10.04 LTS. By default, guests are confined by an AppArmor profile which provided partial protection against this flaw. It was discovered that libvirt would create new VMs without setting a backing store format. A privileged attacker in the guest could exploit this to read arbitrary files on the host. This issue did not affect Ubuntu 8.04 LTS. In Ubuntu 9.10 and later guests are confined by an AppArmor profile which provided partial protection against this flaw. Jeremy Nickurak discovered that libvirt created iptables rules with too lenient mappings of source ports. A privileged attacker in the guest could bypass intended restrictions to access privileged resources on the host