source: http://www.securityfocus.com/bid/27559/info

Nilson's Blogger is prone to a local file-include vulnerability because it fails to properly sanitize user-supplied input.

An attacker can exploit this vulnerability using directory-traversal strings to include local files in the context of the webserver process. This may allow the attacker to obtain potentially sensitive information; other attacks are also possible.

This issue affects Nilson's Blogger 0.11; other versions may also be vulnerable. 

http://www.example.com/comments.php?thispost=../../../../../../../../../../etc/passwd 