Movable Type XMLRPC API provided by Six Apart Ltd. contains a command injection vulnerability. Sending a specially crafted message by POST method to Movable Type XMLRPC API may allow arbitrary Perl script execution, and an arbitrary OS command may be executed through it. Affected products and versions are as follows: Movable Type 7 r.5202 and earlier, Movable Type Advanced 7 r.5202 and earlier, Movable Type 6.8.6 and earlier, Movable Type Advanced 6.8.6 and earlier, Movable Type Premium 1.52 and earlier, and Movable Type Premium Advanced 1.52 and earlier. Note that all versions of Movable Type 4.0 or later including unsupported (End-of-Life, EOL) versions are also affected by this vulnerability.