GoKawiilMicrosoft to let Teams admins customize blocked file extensions list
Microsoft plans to update Teams' Weaponizable File Protection feature so administrators can customize which file types get blocked in chats and channels, rather than relying solely on Microsoft's default list. The change is listed on the Microsoft 365 roadmap and is expected to roll out starting November 2026 across Android, desktop, iOS, macOS and web.
GoKawiil's interpretation of the reporting above, not reported fact.
Currently admins have no control over which risky file extensions Teams blocks, forcing organizations to accept Microsoft's one-size-fits-all defaults even if their security policies differ. This update fits a broader pattern of Teams hardening against social engineering and malware delivery, alongside other recent additions like blocking external users, blurring suspicious QR codes, and reporting fake guest invites.
- Admins will gain the ability to customize blocked file extensions in Teams instead of using only Microsoft's default list.
- The feature is part of Weaponizable File Protection and rolls out starting November 2026.
- It joins other recent Teams security upgrades targeting phishing, malicious QR codes, and fraudulent guest invitations.
Source: bleepingcomputer.com, 2026-09-18
Published there as: “Microsoft Teams will let admins block custom file extensions”
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