From Microsoft site:
The security update for Windows 10 that is dated August 18, 2015, includes improvements in the functionality of Windows 10 and resolves the following vulnerabilities in Windows:
Windows 10 updates are cumulative. Therefore, this package contains all previously released fixes. If you have previous updates installed, only the new fixes that are contained in this package will be downloaded and installed to your computer.
How to obtain and install the update
Important If you install a language pack after you install this security update, you must reinstall this security update. Therefore, we recommend that you install any language packs that you need before you install this security update. For more information, see Add language packs to Windows.
Method 1: Windows Update
Method 2: Microsoft Update Catalog