source: https://www.securityfocus.com/bid/14765/info

PBLang is affected by a directory traversal vulnerability. This issue is due to a failure in the application to properly sanitize user-supplied input.

Exploitation of this vulnerability could lead to a loss of confidentiality. Information obtained may aid in further attacks against the underlying system; other attacks are also possible. 

http://www.example.com/pblang/setcookie.php?u=../../../../../etc/passwd%00