Microsoft Entra ID Sign-In CSP Blocks Script Injection
Microsoft will enforce a stricter Content Security Policy on the Entra ID sign-in page at login.microsoftonline.com by mid-to-late October 2026, limiting script downloads to trusted Microsoft CDNs and allowing inline scripts only through Microsoft-controlled nonce-based patterns. This matters because it hardens one of the most targeted parts of the authentication flow against script injection attacks, though organizations using browser extensions or custom tools that interact with the sign-in page may need to review compatibility before rollout.