FCM test notifications flood Microsoft Teams users on phones

Microsoft said it was working on to fix an issue that has resulted in its Meet users receiving multiple test notifications on their mobile devices.

Several Google Meet users took to social media platforms like Twitter, Reddit and Microsoft tech community pages late on Thursday to report they were receiving ‘FCM Messages’ on their smartphones.

Firebase Cloud Messaging (FCM) is a free service from Google that lets users reliably deliver push notifications at no cost. People can send two types of messages with FCM — notification messages and data messages.

Microsoft said they were investigating an issue where users are receiving Test notifications on their mobile devices.

“Further updates will be provided under the SI TM221041 in your admin center,” Microsoft 365 Twitter handle commented.

“Our investigation has determined that this issue affects Android users specifically, and we’re working on applying a mitigation. We recommend dismissing these notifications without interacting with them,” it added.

Recently, Google Hangouts users also received FCM Messages test notifications.

These two incidents may be connected to a vulnerability in Google’s push notification service Firebase Cloud Messaging.

A Microsoft Team user posted: “A couple of our users received random notifications on the Teams mobile app this morning. The notification states ‘FCM Message’. Anyone have an idea what’s going on?”

“I received 5 notifications this morning ‘FCM Messages Test Notifications!!!!’ seems it is related to an exploit let’s hope that Microsoft or Google plug it soon, otherwise I’ll be uninstalling the Teams app on my phone,” another commented on Microsoft tech community page.