If you still have an active Facebook account and posted something between May 18 and May 22 — the dates the bug was active — take these steps, stat: Open the app, tap on your notifications, and look for the following message: "Due to a technical error, we recommend you review the audience of your recent posts."
In the notification, Facebook says it has automatically "changed the audience of any posts you made to what you had been using before, just in case." Still, it's worth double checking to ensure those posts intended just for friends — and not all two billion-plus Facebook users around the world — are set to friends-only. To do so, go to your profile, tap the downward arrow at the top of your post, and make sure there is a check mark next "friends", not "public."
In a Facebook Newsroom post, Erin Egan, the company's Chief Privacy Officer, says Facebook is notifying users "out of an abundance of caution" and explains how the error took place:
"This bug occurred as we were building a new way to share featured items on your profile, like a photo. Since these featured items are public, the suggested audience for all new posts – not just these items – was set to public."
In any other year, this privacy mistake might have been nothing more than a tiny blip. But after the Cambridge Analytica data scandal that has dominated the coverage of Facebook in the news cycle this year, this is definitely not the kind of "oops" notification users want to get.