Directory traversal vulnerability in Nexgen FTP Server before 2.2.3.23 allows remote authenticated users to read or list arbitrary files via (1) "..", (2) "\..\" (backslash dot dot), or (3) "/../" sequences in (a) RETR (get), (b) NLST (ls), (c) LIST (ls), (d) RNFR, or (e) RNTO FTP commands.