source: http://www.securityfocus.com/bid/15700/info

phpYellowTM is prone to multiple SQL injection vulnerabilities. These issues are due to a failure in the application to properly sanitize user-supplied input before using it in an SQL query.

Successful exploitation could result in a compromise of the application, disclosure or modification of data, or may permit an attacker to exploit vulnerabilities in the underlying database implementation. 

http://www.example.com/search_result.php?search=url&haystack=[SQL]