Zope before 2.2.1 does not properly restrict access to the getRoles method, which allows users who can edit DTML to add or modify roles by modifying the roles list that is included in a request.
http://www.zope.org/Products/Zope/Hotfix_08_09_2000/security_alert
http://www.securityfocus.com/bid/1577
http://www.redhat.com/support/errata/RHSA-2000-052.html
http://www.debian.org/security/2000/20000821
http://archives.neohapsis.com/archives/bugtraq/2000-08/0259.html
http://archives.neohapsis.com/archives/bugtraq/2000-08/0198.html