Multiple directory traversal vulnerabilities in HTTP File Server (HFS) before 2.2c, when account names are used as log filenames, allow remote attackers to create arbitrary (1) files and (2) directories via a .. (dot dot) in an account name, when requesting the / URI; and (3) append arbitrary data to a file via a .. (dot dot) in an account name, when requesting a URI composed of a "/?%0a" sequence followed by the data.
