从MT的官方博客上可以看到，MT4.x的博客都需要安全更新，最新版是MT4.12，大家可以在这里下载到最新版。

下面是官方博客上的更新理由：

      A detailed description of the vulnerability can be found below, but in short a cross-site scripting (XSS) vulnerability has been found in Movable Type's built-in search feature, which could be exploited by malicious parties to execute javascript without permission.

是MT内置的搜索功能有点缺陷。

受到影响的MT版本有：

Movable Type 4.0, 4.01, 4.01a (Personal and Commercial)
Movable Type 4.1 (Open Source, Personal and Commercial)
Movable Type Community Solution 1.0, 1.0a
Movable Type Community Solution 1.5
Movable Type Enterprise Solution 1.0