It came to our attention a couple of hours ago that BlogEngine.NET 1.4 have a security issue in how it handles comments. The issue have been delt with and an easy-to-install patch have been released at CodePlex. 

It is not a serious security issue that can bring your blog to its knees or exposes your passwords, but it is highly recommended that you download the patch and apply it to your installation. It is as simple as uploading a single file. Sorry for the inconvenience.

Download the patch