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

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

SharePoint 2010 Suite:

  • KB 4493223 – SharePoint Foundation 2010

SharePoint 2013 Suite:

  • KB 4493210 – SharePoint Foundation 2013 (core component)
  • KB 4493204 – Office Web Apps Server 2013

SharePoint 2016 Suite:

  • KB 4493195 – SharePoint Server 2016 (language independent)

SharePoint 2019 Suite:

  • KB 4493194 – SharePoint Server 2019 (language independent)

Office Online Server:

  • KB 4493192 – 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. After deploying the SharePoint 2016 February PU we are missing the IDs from our Document ID links on files. Old links are still opening the expected files but when we try to get a link for a document via the ellipsis (…) it just has “_layouts/15/DocIdRedir.aspx” with no “?ID=XXXXXXX”


    1. Hi Joel,
      this is a known issue in February 2021 CU for SharePoint 2016 and is documented in the Known Issues section of the KB article for this CU.
      It is recommended to read the KB articles in detail before applying a CU to be aware of potential issues.


  2. I have deployed Security update for SharePoint foundation server 2013 February 2021 and facing an issue in the search administration page as it says
    ‘The base type ‘Microsoft.Office.Server.Search.Internal.UI.SearchAdministration’ is not allowed for this page. The type Microsoft.Office.Server.Search.Internal.UI.SearchAdministration, Microsoft.Office.Server.Search, Version=, Culture=neutral, PublicKeyToken=71e9bce111e9429c could not be found or it is not registered as safe.

    Also, in our farm we have installed the security updates in both the servers but in one of the servers still after the installation it says Installation Required. Can you be able to help on this issue and suggest your recommendation for the same.
    Your help is much appreciated.

    Thanks in advance.


    1. Hi Bharati,
      the error indicates that the SharePoint config wizard was not run after installing the update.
      The config wizard would apply the necessary web.config changes to prevent the “is not allowed for this page” error.
      About install required: if you run the config wizard on the machine where it states that the fix is not installed but is installed should resolve the issue as it updates the info about the installed fixes in the config db.


  3. Thanks Stefan for the quick reply. I will try the steps as per your recommendation and will update in case if I still face any issue during the process.

    Thanks again for the quick help.


  4. One more thing this time the SharePoint security updates were pushed by WSUS. Will that make any difference as we deploy the updates on the SP servers following the patching process document means stopping the search service application and then deploying the security updates.


  5. Hi Stefan,

    I tried the steps as per your recommendation but still facing the same issue while running config wizard, it listed out the files which are missing in the another server even the installed files are available in the control panel. I tried to install the files on the missing server, still the issue not resolved it said the files are already there. Any help is much appreciated on this


    1. If you need assistance to resolve the issue please open a ticket with Microsoft support.



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