MWChat contains a flaw that may allow a remote attacker to carry out an SQL injection attack. The issue is due to the 'chat.php' script not properly sanitizing user-supplied input to the 'Username' variable. This may allow a remote attacker to inject or manipulate SQL queries in the back-end database.
Upgrade to version 6.9 or higher, as it has been reported to fix this vulnerability. An upgrade is required as there are no known workarounds.