The remote host is vulnerable to a SQL Injection attack.
The version of MyBB installed on the remote host fails to sanitize input to the 'options[disablesmilies]' parameter of the 'private.php' script before using it in a SQL query. An attacker exploiting this flaw would need to be able to authenticate with a valid user ID and send data to the private.php script. Successful exploitation would result in the attacker executing arbitrary SQL commands on the database server utilized by MyBB.
Upgrade to version 1.2.12 or higher.