If you're a Facebook user you'll have probably seen the alert above pop up on your account in the past few days.
It's asking you to check over any posts you made or shared between May 18 and 22, because a bug may have accidentally turned your private posts public.
Facebook estimates that the bug affected 14 million users during that five day period, which happened as the social network was testing a new way to share featured items on profile pages.
Every time you post or share to your wall, Facebook has a dropdown "audience selector" that lets you pick who gets to view the post.
Because of the glitch, this selector was automatically set to "public" on affected accounts, meaning those who only meant to share posts with their friends or acquaintances may have accidentally posted them so that anyone can see them.
Although Facebook says the bug was operating between May 18-22, when the fix began, you might want to check posts up to May 27, by when it was fully corrected.
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"Out of an abundance of caution we are letting anyone affected know today and asking them to review Facebook posts they made during that time," it announced on Thursday.
"If you posted publicly, you’ll see a notification when you log in that leads to a page with more information – including a review of posts during this period."
It's another black mark at a tumultuous time for Facebook, which is striving to regain credibility after the Cambridge Analytica fiasco revealed the extent to which user data was being shared.