CVE 2008-4079

Cross-site scripting (XSS) vulnerability in Movable Type (MT) 4.x through 4.20, and 3.36 and earlier; Movable Type Enterprise 4.x through 4.20, and 1.54 and earlier; and Movable Type Community Solution allows remote attackers to inject arbitrary web script or HTML via unspecified vectors.

See the CVE page on Mitre.org for more details.