Blog Engine released a fix, which will solve the memory leak.  The leak was in the related post server control. You can download the fix from Codeplex. Just download unzip and replace the file inside your App_Code folder. It is recomended that you keep a back up copy of the existing page. The download zip also contains a text file which will guide you how to do it.

If you want to read more about the memory leak, you can read Mads Kristensen’s post regarding that here