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

Starting March 1, 2026, SharePoint Online will enforce Content Security Policy (CSP), blocking scripts from untrusted sources in custom SPFx solutions. To avoid disruptions, ensure all scripts come from trusted sources and move inline scripts to files. CSP enforcement can be postponed 90 days via PowerShell.