source: https://www.securityfocus.com/bid/4167/info

The Extreme Message Board (XMB) 1.6 Magic Lantern pre-beta version reportedly allows JavaScript and HTML to be entered in messages. This can be achieved by entering script or HTML between [img] and [/img] tags in a forum message.

This has been fixed in the 1.6 Magic Lantern final beta version of XMB.

[img]javasCript:alert('Hello world.')[/img]