Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
With this vulnerability an attacker can read many sensitive files like configuration files, or the /proc/self/environ file, that contains the environment variable used by the web server that includes database credentials. If the web server user is root, an attacker will be able to read any file in the system.
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.