Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Multiple directory traversal vulnerabilities in DM Guestbook 0.4.1 and earlier allow remote attackers to include and execute arbitrary local files via a .. (dot dot) in (1) the lng parameter to (a) guestbook.php, (b) admin/admin.guestbook.php, or (c) auto/glob_new.php; or (2) the lngdefault parameter to auto/ch_lng.php.
CWE-22 - Path Traversal
Path traversal (or directory traversal), is a vulnerability that allows malicious users to traverse the server's root directory, gaining access to arbitrary files and folders such as application code & data, back-end credentials, and sensitive operating system files. In the worst-case scenario, an attacker could potentially execute arbitrary files on the server, resulting in a denial of service attack. Such an exploit may severely impact the integrity, confidentiality, and availability of an application.