Cross-site scripting (XSS) vulnerability in Six Apart (formerly Six Apart KK) Movable Type (MT) Pro 5.13 allows remote attackers to inject arbitrary web script or HTML via the comment section.
https://exchange.xforce.ibmcloud.com/vulnerabilities/79521
https://euvd.enisa.europa.eu/vulnerability/EUVD-2012-1521
http://www.securityfocus.com/bid/56160
http://www.exploit-db.com/exploits/22151
http://www.cloudscan.me/2012/10/cve-2012-1503-movable-type-pro-513en.html
http://packetstormsecurity.org/files/117564/Movable-Type-Pro-5.13en-Cross-Site-Scripting.html