SharePoint Online – Major Update – Content Security Policies (CSP) are coming to SharePoint Online and might impact custom SPFx solutions

Hi All,

Greetings. LIFE IS BEAUTIFUL 🙂

Today, I am sharing one of the major updates related to SharePoint Online.

Major Update: Content Security Policies (CSP) are coming to SharePoint Online and might impact custom SPFx solutions

Details

• Microsoft is improving SharePoint Online security via Content Security Policy (CSP) enforcement.
• Earlier CSP is applied in reporting mode.
• From March 1, 2026, the Content Security Policy will be enforced which will prevent the loading of script (e.g. JavaScript) from non-allowed sources.
• If we are using SPFx and SPFx solutions loads scripts from locations which are not allowed. These scripts will be blocked.
• In most cases SPFx solutions use and load script from allowed locations, but that’s not always the case.
• Any script from a not allowed location will be blocked, the same applies for any inline script usage.
• SPFx solutions whose script is getting blocked will not work anymore as designed, impacting business scenarios depending on those solutions.

To prevent solutions from breaking there you need to

• Make sure all used script locations are trusted script sources.
• This can be done without updating the SPFx solution
• Move all inline script to script files which can then be defined as trusted source. This will need updating the SPFx solution!

Microsoft 365 Roadmap ID: 485797 – SharePoint: Content Security Policy Control in Tenant Administration

How to postpone CSP enforcement by 90 days

• Using PowerShell CMDLET – Set-SPOTenant

Set-SPOTenant -DelayContentSecurityPolicyEnforcement $true

Note – This option will be available in the SPO Management Shell version 16.0.26712.12000 (November 2025) or higher.

References

• Support for Content Security Policy (CSP) in SharePoint Online – https://learn.microsoft.com/en-us/sharepoint/dev/spfx/content-securty-policy-trusted-script-sources
• Microsoft 365 Roadmap ID: 485797 – SharePoint: Content Security Policy Control in Tenant Administration – https://www.microsoft.com/en-in/microsoft-365/roadmap?id=485797

Thanks for reading! HAPPY SHARING 🙂