A flaw was found in OpenStack Keystone. A remote attacker could exploit this vulnerability by sending a large HTTP request, specifically by providing a long tenant name when requesting a token. This could lead to a denial of service, consuming excessive CPU and memory resources on the affected system.

OpenStack Keystone 2012.1.3 does not invalidate existing tokens when granting or revoking roles, which allows remote authenticated users to retain the privileges of the revoked roles.