The August 2015 Cumulative Update for SharePoint 2013 contains numerous hotfixes and improvements for SharePoint Foundation 2013 and SharePoint Server 2013. The cumulative update package is multilingual and contains updates for all languages.

Before you start
Since June 2014 the Cumulative Updates for SharePoint products releases on a monthly basis.
Since May 2015 the server proofing tools are included in the cumulative updates.
This cumulative update includes all patches since the Service Pack 1 release, but not the Service Pack 1 itself. You must install the Service Pack 1 before installing this cumulative update. Read how-to install Service Pack 1.
Because of the file size the cumulative update package has been divided in three parts; ubersrv.exe, ubersrv_1.cab and ubersrv_2.cab. You have to put them all in the same folder.
The July CU changes the database schema for the Search analytics reporting database to support URLs up to 4000 characters. The Search crawler expects an updated database schema and is going to fail if the SharePoint Configuration Wizard (psconfig) hasn’t been run right after the installation (follow the installation instructions below).

Installation instructions

  • Create a SharePoint Farm Backup.
  • Download all SharePoint Foundation and SharePoint Server packages.
  • Extract the previously downloaded files with a double-click.
  • Click «Continue»
  • Define the path in which you would like to extract the installation binaries and click OK. Use the same destination path for the other files.
  • Run the extracted EXE file as administrator.
  • Accept the license terms and click «Continue».
  • Repeat the previous two steps for the other EXE files in this folder.
  • Apply the updates to each SharePoint server in the farm.
  • As soon as the installation of the cumulative update has finished on all servers, run the SharePoint Configuration Wizard successively on each SharePoint server in the farm.
  • Restart the User Profile Service on affected servers.

Hotfix KB3055004 for SharePoint Foundation 2013: August 11, 2015
Download
Description of the SharePoint Foundation 2013 update package

Hotfix KB3055009 for SharePoint Server 2013: August 11, 2015
Download
Description of the SharePoint Server 2013 update package

Hotfix KB3055005 for Project Server 2013: August 11, 2015
Download
Description of the Project Server 2013 update package

Hotfix KB3055003 for Office Web Apps Server 2013: August 11, 2015
Download
Description of the Office Web Apps Server 2013 update package
This is a security fix, please refer to SharePoint updates are no longer available through Windows Update

SharePoint 2013 update portal
http://technet.microsoft.com/en-us/sharepoint/ee748587.aspx