The libvirt driver in OpenStack Compute (Nova) before 2013.2.2 and icehouse before icehouse-2 allows remote authenticated users to cause a denial of service (disk consumption) by creating and deleting instances with unique os_type settings, which triggers the creation of a new ephemeral disk backing file.
OpenStack Compute (Nova) Grizzly 2013.1.4, Havana 2013.2.1, and earlier uses world-writable and world-readable permissions for the temporary directory used to store live snapshots, which allows local users to read and modify live snapshots.