Published:2009/04/24 Last Updated:2009/06/19

Information from Six Apart KK

Vulnerability ID:JVN#97248625
Title:Movable Type cross-site scripting vulnerability
Status:Vulnerable

This is a statement from the vendor itself with no modification by JPCERT/CC.

This issue has been fixed by the latest version

http://www.movabletype.org/2009/06/mt_4261_a_small_patch_release.html