source: https://www.securityfocus.com/bid/10000/info

A vulnerability has been reported to exist in Cloisterblog that may allow a remote attacker to access information outside the server root directory. The problem exists due to insufficient sanitization of user-supplied data. The issue may allow a remote attacker to traverse outside the server root directory by using '../' character sequences.

Successful exploitation of this vulnerability may allow a remote attacker to gain access to sensitive information that may be used to launch further attacks against a vulnerable system. 

http://www.example.com/cloisterblog/journal.pl?syear=2004&sday=11&smonth=../../../../../../../../etc/passwd%00