Movable Type before 4.38, 5.0x before 5.07, and 5.1x before 5.13 allows remote attackers to take control of sessions via unspecified vectors related to the (1) commenting feature and (2) community script.
http://www.securitytracker.com/id?1026738
http://www.securityfocus.com/bid/52138
http://www.movabletype.org/documentation/appendices/release-notes/513.html
http://www.movabletype.org/2012/02/movable_type_513_507_and_438_security_updates.html
http://www.debian.org/security/2012/dsa-2423