MC1193419 | (Updated) Content Security Policies (CSP) are coming to SharePoint Online and might impact your custom SPFx solutions

Service

SharePoint Online

Last Updated

2026-03-13T19:26:48.223Z

Published

2025-12-09T00:19:20Z

Message ID

MC1193419

Updated March 13, 2026: We have updated the timeline. Thank you for your patience. We’re improving SharePoint Online security via Content Security Policy (CSP) enforcement. Currently CSP is applied in reporting mode but as of March 1, 2026, the Content Security Policy will be enforced which will prevent the loading of script (e.g. JavaScript) from non-allowed sources. This message center post replaces MC1055557 (April 2024). This change is associated with Microsoft 365 Roadmap ID: 485797 [When this will happen:] This will be implemented starting March 1, 2026 and should complete by March 20, 2026. [How this will affect your organization:] If your organization extended SharePoint Online using...

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