Q: If Microsoft releases a replacement for a buggy security update, do we need to uninstall the earlier update before installing the replacement?
A: It shouldn't be necessary to uninstall the buggy update. Windows Server Update Services (WSUS) will either reinstall the new version or prompt you to approve the update for installation, depending on your configuration. In some cases, you must rerun discovery for Windows to realize that a new version of the update needs to be installed on applicable computers.
—Randy Franklin Smith