An issue was discovered in the default FilterScheduler in OpenStack Nova 16.0.3. By repeatedly rebuilding an instance with new images, an authenticated user may consume untracked resources on a hypervisor host leading to a denial of service, aka doubled resource allocations. This regression was introduced with the fix for OSSA-2017-005 (CVE-2017-16239); however, only Nova stable/pike or later deployments with that fix applied and relying on the default FilterScheduler are affected.