Microsoft Defender for Office 365 introduces prompt injection protection to detect and block malicious email content targeting AI assistants. High confidence threats are auto-quarantined. Available to Plan 2 and Microsoft 365 E5 users, enabled by default from early July 2026. No action required; review workflows and inform teams.
Applies to: Microsoft Defender XDR
Source: mc.merill.net — data via Merill Fernando's open archive (MIT).