The lead European Union data privacy regulator for Meta fined the social media giant 251 million euros ($263.5 million) on Tuesday for a 2018 Facebook security breach that affected 29 million users.

Meta notified Ireland’s Data Protection Commission at the time that cyber attackers had exploited a vulnerability in Facebook’s code that impacted the “View As” feature that lets users see what their own profile looks like to someone else.

That led to a breach in personal data including users’ full name, contact details, location, place of work, date of birth, religion, gender and their children’s personal data, the DPC said.

Meta remedied the breach shortly after its discovery, the DPC said. Of the 29 million Facebook accounts impacted globally, about 3 million were based in the EU and European Economic Area.