Instagram admitted to the bug after Selena Gomez's account was hacked.
An Instagram bug meant hackers gained access to celebrity users' phone numbers and email addresses, the company admitted on Wednesday.
Instagram didn't give details of the bug, but said it related to its application programming interface, or API. We first saw news of the bug via The Verge.
"We recently discovered that one or more individuals obtained unlawful access to a number of high-profile Instagram users' contact information — specifically email address and phone number — by exploiting a bug in an Instagram API," an Instagram spokesman said. "No account passwords were exposed. We fixed the bug swiftly and are running a thorough investigation."
The admission comes days after hackers accessed Selena Gomez's Instagram account and posted nude pictures of her ex-boyfriend Justin Bieber.
The company has notified its other verified users to be on the lookout for suspicious emails or calls. It's possible the hackers first obtained Gomez's email address and phone number, then used these details to access her Instagram account. The photos of Bieber have since been deleted from her account.
This isn't the first time celebrities on Instagram have been hacked. A hacker supposedly accessed US model Blac Chyna's Instagram account and published private messages showing she had left Rob Kardashian. Hackers also posted odd messages and cartoon images to Tom Hiddleston's account last year.