The MITRE CVE dictionary describes this issue as:
OpenStack Keystone, as used in OpenStack Folsom before folsom-rc1 and OpenStack Essex (2012.1), allows remote attackers to add an arbitrary user to an arbitrary tenant via a request to update the user's default tenant to the administrative API. NOTE: this identifier was originally incorrectly assigned to an open redirect issue, but the correct identifier for that issue is CVE-2012-3540.
Find out more about CVE-2012-3542 from the
MITRE CVE dictionary dictionary and