source: http://www.securityfocus.com/bid/27688/info

PowerScripts PowerNews is prone to multiple local file-include vulnerabilities because it fails to properly sanitize user-supplied input.

Exploiting these issues may allow an attacker to access potentially sensitive information and execute arbitrary local scripts in the context of the affected application.

PowerNews 2.5.6 is vulnerable; other versions may also be affected. 

http://example.com/[installdir]/pnadmin/categories.inc.php?subpage=../../../../../../../../../../../../../etc/passwd%00 