The Subuser module before 6.x-1.8 for Drupal does not properly check "switch subuser" permissions, which allows remote authenticated parent users to change their role by switching to a subuser they created.
http://www.openwall.com/lists/oss-security/2012/10/07/1
http://www.openwall.com/lists/oss-security/2012/10/04/6