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This security update resolves a Microsoft SharePoint Server remote code execution vulnerability. To learn more about the vulnerability, see Microsoft Common Vulnerabilities and Exposures CVE-2024-21426.


  • This is build 16.0.17328.20136 of the security update package.

  • To apply this security update, you must have the release version of Microsoft SharePoint Server Subscription Edition installed on the computer.

Improvements and fixes

This security update introduces the SharePoint Server Subscription Edition Version 24H1 feature update. This feature update will be included in all SharePoint Server Subscription Edition public updates going forward. For more information about this feature update, see New and improved features in SharePoint Server Subscription Edition Version 24H1.

This security update contains improvements and fixes for the following nonsecurity issues in SharePoint Server Subscription Edition:

  • Allows users to disable SharePoint's Content Security Policy (CSP) HTTP header in SharePoint Pages. If you don't want to enable the SharePoint CSP HTTP header in SharePoint Pages, you can run the following cmdlets in PowerShell:

    Add-PSSnapin Microsoft.SharePoint.PowerShell
    $farm = Get-SPFarm
    $farm.EnableCSPHeaderForPage = $false

  • Fixes an issue in which the modern List web part freezes when you select the See all link for a grouped view if the site URL contains the apostrophe (') character.

  • Fixes an issue in which the Edit button overlaps the multiline field title in the list item editing pane when you use right-to-left (RTL) languages.

  • Fixes an issue in which horizontal navigation of the communication site doesn't reflect the current site correctly.

  • Fixes an issue in which SharePoint site theme customization delays the login form by 5 seconds while the form tries to load.

  • Fixes an issue in which plain text will be rendered as a hyperlink in quick edit mode.

  • Fixes an issue in which the classic UI doesn't show the correct status of a subsite.

Known issues in this update

  • After you install this security update, you may encounter an issue in which servers cannot join an existing SharePoint farm. For more information, see Can't add a server to a SharePoint farm if the farm contains a certificate managed by Certificate Management (KB5037978).

  • This security update also introduces a newer version of the Microsoft.Owin component. Because this component's version is referenced in SharePoint Server's Web.config files, you must run an upgrade action to update the reference in these Web.config files. If you install this security update without running the upgrade action, you will receive the following error message when you browse to SharePoint sites:

    Could not load file or assembly 'Microsoft.Owin, Version=, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.

    After you install this security update, run the upgrade action by using one of the following methods:

    • Start the SharePoint Products and Technologies Configuration Wizard (PSConfigUI.exe) and upgrade.

    • Run the SharePoint Products Configuration Wizard (PSCONFIG.EXE) command line tool:

      PSCONFIG.EXE -cmd secureresources -cmd services -install -cmd installfeatures -cmd applicationcontent -install -cmd upgrade -inplace b2b -wait

    • Run the following PowerShell commands:

      Install-SPFeature -AllExistingFeatures

    After you run this upgrade action, the error message disappears.

    This behavior is by design because the new component version must be registered in SharePoint Server's Web.config files.

    This issue will affect the ability of users to do "zero downtime patching" (ZDP), as described in SharePoint Server zero downtime patching steps. This is because SharePoint sites won't be accessible until the upgrade action is run. Users should be prepared to install the update during a maintenance window when downtime is acceptable.

    Alternatively, users can avoid downtime by manually editing the Web.config file for each of their web applications immediately after the update is installed on a given server and before the server is returned to the load balancing rotation. To do this, follow these steps:

    1. Locate the following lines in the configuration > runtime > assemblyBinding section of the Web.config file:

           <assemblyIdentity name="Microsoft.Owin" publicKeyToken="31bf3856ad364e35" culture="neutral" />
           <bindingRedirect oldVersion="" newVersion="" />

    2. Replace the located text with the following lines:

           <assemblyIdentity name="Microsoft.Owin" publicKeyToken="31bf3856ad364e35" culture="neutral" />
           <bindingRedirect oldVersion="" newVersion="" />

    After the update is installed on all servers, users can run the upgrade action. Manually editing the Web.config file won't interfere with the upgrade action.

How to get and install the update

Method 1: Microsoft Update

This update is available from Microsoft Update. When you turn on automatic updating, this update will be downloaded and installed automatically. For more information about how to get security updates automatically, see Windows Update: FAQ.

Method 2: Microsoft Update Catalog

To get the standalone package for this update, go to the Microsoft Update Catalog website.

Method 3: Microsoft Download Center

You can get the standalone update package through the Microsoft Download Center. Follow the installation instructions on the download page to install the update.

More information

Security update deployment information

For deployment information about this update, see Deployments - Security Update Guide.

Security update replacement information

This security update replaces previously released security update 5002540.

File hash information

File name

SHA256 hash



File information

Download the list of files that are included in security update 5002564.

Information about protection and security

Protect yourself online: Windows Security support

Learn how we guard against cyber threats: Microsoft Security

Change history

The following table summarizes some of the most important changes to this topic.



March 20, 2024

Added a "Known issues in this update" section to describe an issue that users may experience.

April 9, 2024

Added a new item to the "Known issues in this update" section (cannot join servers).

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