The Facebook app for iOS has been activating iPhone cameras without their permission.

Website designer Joshua Maddux noticed the issue while scrolling through the Facebook app. As he transitioned between different Pages (between a person's bio photo and the profile section, for instance), he spotted the app showing his camera opening up alongside the main Facebook feed.

Maddux uploaded a video on Twitter, demoing the potential privacy issue in action. A bug in the app will briefly show it displaying the main Facebook feed on top of the iPhone's camera view. In this case, the camera is pointed at a carpet. But it got Maddux wondering if the Facebook app might be secretly recording more information than users bargained for.

"This is proof that they are accessing your back camera. They may also be accessing the front camera," he said in a tweet.

However, Facebook says the camera activation is simply an error. "We recently discovered our iOS app incorrectly launched in landscape. In fixing that last week in v246 we inadvertently introduced a bug where the app partially navigates to the camera screen when a photo is tapped. We have no evidence of photos/videos uploaded due to this," said Facebook VP Guy Rosen in a tweet.

Still, because the app comes from Facebook—a company with a reputation for collecting people's data without their permission—the camera activation set off alarm bells for Maddux, who says he's reproduced the issue across five different iPhones running iOS 13.2.2. Other Twitter users and media outlets have also reproduced the same privacy issue while using the iOS version of the app.

Rosen said Facebook has submitted a fix to the iOS App Store. According to Maddux, iPhone owners can also patch the problem on their own. In the Settings menu on iOS, disable camera and microphone access for the Facebook app.