source: http://www.securityfocus.com/bid/22081/info

SmE File Mailer 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 implementation.

This issue affects version 1.21; other versions may also be vulnerable. 

The following input to the login form is sufficient to exploit this issue:

Login: admin
Password: anything' OR 'x'='x