I just want to accent that this security advisory is related not to Image Uploader only. This update stoppes using of unsafe File Downloader builds also. So if you have File Downloader installed on your site you need to check its version. Version 1.0.110 and all versios 2.x are safe and out of killbit. If you have version before 1.0.110 installed on your site it stops working after Microsoft update 953839 is installed on a computer.
To update your 1.x version of File Downloader to safe one you need to download version 1.0.110 from legacy downloads.