On iOS 11, Apple introduced a new way to protect user privacy by letting you hide the contents of your notifications on your iPhone's lock screen until you unlock the device with Touch ID or Face ID. Brazilian site Mac Magazine has found that, even with this feature enabled, anyone can reveal the contents of your hidden notifications simply by asking for a little help from the virtual assistant.
The bug works on the most recent iteration of iOS (iOS 11.2.6) and is said to work on the iOS 11.3 beta as well.
According to a report from Engadget, Apple has confirmed to the publication that they are aware of the problem and will be issuing a fix. In the latter case, users will at the very least take steps to keep their phone away from prying eyes.
Until then, you can head to your iPhone's settings to stop Siri from reading your notifications aloud. However it should be noted that this only seems to affect third-party apps and services, and that Apple's own apps like Messages do not appear to have been affected by the bug.
Apple started hiding notification previews by default when it rolled out iOS 11 past year.
We've reached out to Apple and will update this story if we receive a response. As of now, you can fix this issue by disabling Siri while your iOS device is locked. Until a fix has been released, we suppose users who are anxious about this can maybe try disabling Siri.
Another option is to turn off lock screen notifications to apps you think to carry sensitive information.
Test the bug for yourself: Go to Settings Notifications Select an app (say WhatsApp) Show Previews Select "When Unlocked".