Microsoft should fix Outlook privacy issue that sends out attendees' details without consent when forwarding

It's actually a design mistake rather than a privacy "bug."

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Key notes

  • Outlook sometimes reveals hidden attendees’ details when forwarding, a privacy concern.
  • Despite initial attempts to hide participant lists, forwarding meetings can expose all attendees.
  • This isn’t a privacy bug, but rather from its design. You can’t change details once an event is created.

Microsoft Outlook is one of the most popular email providers out there. Lots of organizations and businesses use it, especially now that it has Copilot AI, but there’s one thing that needs to be patched: sometimes, it sends out hidden attendees’ details when forwarding. 

The problem is, that whenever you forward a meeting invitation in Outlook, even when the participant list is initially hidden, the new recipient can still receive the full list of original participants. It poses an obvious privacy concern because it can expose their emails without consent. 

Folks online are calling it a major privacy bug and privacy flaw, but it is actually by design. You can only hide attendees’ details while creating the event. Once it’s created, you can’t hide it when you forward or send updates. Of course, it’s not an ideal situation when you have a meeting or some information that isn’t intended for “the new guy” to know who else gets the email.

And in fact, that’s not the only privacy concern Outlook has been subject to in the past few weeks. Not too long ago, we reported that Proton Mail, an encrypted email service, raised concerns over Microsoft’s way of handling data collection in Outlook and how over 800 third parties have used its data for (mainly) advertising purposes, among other things.

Oof.