SharePoint security fixes released with January 2021 PU and offered through Microsoft Update

Below are the security fixes for the SharePoint OnPrem versions released this month.

SharePoint 2010 Suite:

  • KB 4493187 – SharePoint Foundation 2010
  • KB 4493178 – Word Automation Services for SharePoint 2010
  • KB 4486736 – Excel Services for SharePoint 2010
  • KB 4493183 – Office Web Apps Server 2010

SharePoint 2013 Suite:

  • KB 4493175 – SharePoint Foundation 2013 (core component)
  • KB 4486683 – Word Automation Services for SharePoint 2013
  • KB 4486724 – Excel Services for SharePoint 2013
  • KB 4493171 – Office Web Apps Server 2013

SharePoint 2016 Suite:

  • KB 4493163 – SharePoint Server 2016 (language independent)
  • KB 4493167 – SharePoint Server 2016 (language dependent)

SharePoint 2019 Suite:

  • KB 4493162 – SharePoint Server 2019 (language independent)
  • KB 4493161 – SharePoint Server 2019 (language dependent)

Office Online Server:

  • KB 4493160 – Office Online Server
See the Security Update Guide below for more details about the relevant fixes:

More information:

Please ensure to have a look at the SharePoint Patching Best Practices before applying new fixes.


  1. Hi Stefan, Happy New Year!
    One question about patching… For fix this issues:

    Fixes an issue in which the navigation pane will be hidden when users change some Search Admin settings in a Search Service Application.
    Fixes an issue in which Business Connectivity Services (BCS) crawls of the .NET Connectivity Assemblies, Web services or Custom type don’t work.

    I noticed in various Microsoft articles that you need to install multiple patches to fix the problem, in particular this:

    Description of the security update for SharePoint Foundation 2013: December 8, 2020 (KB4493138)
    Description of the security update for SharePoint Foundation 2013: December 8, 2020 (KB4486696)
    December 8, 2020, update for SharePoint Enterprise Server 2013 (KB4486758)

    About January PU which patch should i install to reproduce the December patches listed above?

    Thank you very much


  2. I have installed January patches for 2013 and 2016 and I think there is problem with patch at these two version which is the database schema version not updated to January it keeps December version.


  3. Does January CU has a bug fix for September’s SharePoint 2016 release?


    1. For which issue exactly are you looking for a fix?


  4. After installing KB 4493182 – Project Server 2010 January 2021 CU, I am getting below error message.

    Could not found Microsoft.Office.Project.PWa.Applicationpages.ProjectDrillDownPage from assembly ‘Microsoft.Office.project.Server.Pwa.ApplicationPages’


    1. Hi Prasad,
      did you run the SharePoint Configuration Wizard after installing the fix?


  5. Yes
    It was successfully completed , I cross checked that Central admin > upgrade and Migration> check upgrade status and also update the Patch and Build version as well


    1. After installation of fix – restarted all Servers and run SharePoint Configuration wizard successfully


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