Microsoft Teams lets admins block custom file extensions

Microsoft is upgrading Weaponizable File Protection in Teams so administrators can choose which file types users may send, reducing the risk of malware spreading through the app. The feature previously only auto-scanned dangerous attachments, with rollout targeted for November 2026.

• Admins can customize blocked file types or keep Microsoft's default list
• Automated scanning of Teams attachments began rolling out in early 2026
• The new controls are slated for a November 2026 rollout
• Microsoft says Teams traffic bypasses secure email gateways, making lures effective