Absolute path directory traversal vulnerability in (1) MERAK Mail Server for Windows 8.3.8r with before IceWarp Web Mail 5.6.1 and (2) VisNetic MailServer before 8.5.0.5 allows remote authenticated users to include arbitrary files via a modified language parameter and a full Windows or UNC pathname in the lang_settings parameter to mail/index.html, which is not properly sanitized by the validatefolder PHP function, possibly due to an incomplete fix for CVE-2005-4558.