OpenStack Identity (Keystone) Folsom, Grizzly 2013.1.3 and earlier, and Havana before havana-3 does not properly revoke user tokens when a tenant is disabled, which allows remote authenticated users to retain access via the token.
https://bugs.launchpad.net/ossn/+bug/1179955
http://www.ubuntu.com/usn/USN-2002-1
http://rhn.redhat.com/errata/RHSA-2013-1524.html
http://lists.fedoraproject.org/pipermail/package-announce/2013-September/116489.html