Openstack Compute (Nova) Folsom, 2012.1, and 2011.3 does not limit the number of security group rules, which allows remote authenticated users with certain permissions to cause a denial of service (CPU and hard drive consumption) via a network request that triggers a large number of iptables rules.

Nova 2011.3 and Essex, when using the OpenStack API, allows remote authenticated users to bypass access restrictions for tenants of other users via an OSAPI request with a modified project_id URI parameter.