Ubuntu Security Notice 2630-1 – Matt Tait discovered that QEMU incorrectly handled the virtual PCNET driver. A malicious guest could use this issue to cause a denial of service, or possibly execute arbitrary code on the host as the user running the QEMU process. In the default installation, when QEMU is used with libvirt, attackers would be isolated by the libvirt AppArmor profile. Kurt Seifried discovered that QEMU incorrectly handled certain temporary files. A local attacker could use this issue to cause a denial of service. Various other issues were also addressed.