REDHAT-BUG-2430312: High severity Openstack OpenStack Nova vulnerability

Unconstrained disk format handling vulnerability in OpenStack Nova when invoking the qemu-img utility. The flaw occurs because Nova does not strictly enforce the expected disk image format before calling qemu-img. An authenticated attacker can write a crafted QCOW2 header to a raw ephemeral or root disk. When Nova later performs operations such as instance resize, qemu-img interprets the disk as QCOW2 and overwrites arbitrary files on the compute host that Nova has write access to. This can be exploited without additional privileges or user interaction, allowing attackers to destroy other users’ data, corrupt Nova-managed files, or cause denial of service on the compute node.