Erin Egan, Facebook's chief privacy officer, was quick to apologize for the mistake, but the question remains: can we still trust Facebook?
The flaw affected Facebook's system for 10 days in May, but Facebook says it still plans to notify users who were impacted.
In new accounts, and most others, posts are public by default. If users did not notice the new default suggestion, they unwittingly sent their post to a broader audience than they had intended.
Social media giant Facebook is under the spotlight once again after it revealed 14 million users may have had their posts made public due to a glitch. Facebook usually lets users choose how they want their content to be shared, with basic options being: "Public, Only Friends, Friends Except, Specific Friends or Only me".
Facebook confirmed earlier this week that China-based Huawei - which has been banned by the U.S. military and is a lightning rod for cyberespionage concerns - was among device makers authorized to see user data in agreements that had been in place for years.
Facebook's 2011 consent decree with the FTC calls for the company to get "express consent" from users before sharing their information beyond what they established in their privacy settings. "Since these featured items are public, the suggested audience for all new posts - not just these items - was set to 'public.' The problem has been fixed, and for anyone affected, we changed the audience back to what they'd been using before".
"This bug occurred as we were building a new way to share featured items on your profile, like a photo".
Facebook has stated that these types of notifications will be used going forward to report privacy issues or breaches.
After it became public that tens of millions of users had been affected by the Cambridge Analytica scandal, Facebook took great lengths to beef up users' privacy controls.