Launchpad.net

CVE 2013-0247

OpenStack Keystone Essex 2012.1.3 and earlier, Folsom 2012.2.3 and earlier, and Grizzly grizzly-2 and earlier allows remote attackers to cause a denial of service (disk consumption) via many invalid token requests that trigger excessive generation of log entries.

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