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

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

SharePoint Foundation security fixes also have to be applied on SharePoint Server installations.
SharePoint Server security fixes also have to be applied on Project Server installations.

SharePoint 2010 Suite:

  • KB 4504709 – SharePoint Foundation 2010
  • KB 4504701 – Word Automation Services for SharePoint 2010
  • KB 4504705 – Office Web Apps Server 2010

SharePoint 2013 Suite:

  • KB 4493170 – SharePoint Server 2013 (core component)
  • KB 4493201 – Word Automation Services for SharePoint 2013
  • KB 4504729 – Office Web Apps Server 2013

SharePoint 2016 Suite:

  • KB 4504719 – SharePoint Server 2016 (language independent)
  • KB 4504723 – SharePoint Server 2016 (language dependent)

SharePoint 2019 Suite:

  • KB 4504716 – SharePoint Server 2019 (language independent)
  • KB 4504715 – SharePoint Server 2019 (language dependent)

Office Online Server:

  • KB 4504714 – 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. context menu on list items in SharePoint sites to stop working after update for sharepoint 2010


  2. Hi Stefan,

    I hope that your well,

    I have an issue installing these KB’s (KB 4504716 – KB 4504715 ) on my SharePoint farms.

    My FBA extranet site do not search, its like after install those KBS the crawler is broken and do not work anymore. Theres some incompatibility with these KB and FBA?

    I have two extranet sites one using FBA and other simple extranet, both of sites are using https. My other question is, its possible to have two extranet site using the same protocol and how is the correct form to configure on webbindig? This option is possible to have?

    Thanks in advance.


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