Directory traversal vulnerability in the IMAP service of Rockliffe MailSite before 6.1.22.1 allows remote authenticated users to rename the folders of other users via a .. (dot dot) in the RENAME command.
http://www.vupen.com/english/advisories/2006/0055
http://secunia.com/advisories/18318
http://lists.grok.org.uk/pipermail/full-disclosure/2006-January/041039.html