Facebook, the parent company of Instagram, is looking into how such a major privacy F up came about. It was first originally discovered by a security researcher who tipped off US site TechCrunch.
So what was shared? The personal details of a bunch of Instagram influencer, celebrities, and high-profile brands.
The database was traced back to Mumbai-based social media marketing firm Chtrbox.
Instagram has told the BBC they are investigating.
"We're looking into the issue to understand if the data described - including email and phone numbers - was from Instagram or from other sources," they said in a statement.
"We're also inquiring with Chtrbox to understand where this data came from and how it became publicly available."
