Launchpad.net

CVE 2013-1838

OpenStack Compute (Nova) Grizzly, Folsom (2012.2), and Essex (2012.1) does not properly implement a quota for fixed IPs, which allows remote authenticated users to cause a denial of service (resource exhaustion and failure to spawn new instances) via a large number of calls to the addFixedIp function.

See the CVE page on Mitre.org for more details.