Hackers recently infiltrated HBO’s network and made away with unaired episodes of some of its top shows as well as a script for a future Game of Thrones episode.

HBO confirmed with Entertainment Weekly on Monday that it recently experienced a “cyber incident” that resulted in the compromise of proprietary information. The network didn’t specify exactly what had been stolen.

The publication notes that the hackers claim to have obtained 1.5TB of data and have already put upcoming episode of Ballers and Room 104 online. Also reportedly online is a script that’s allegedly for next week’s episode of Game of Thrones. Thus far, no Game of Thrones episodes have leaked from this season.

HBO said it immediately began investigating the incident and is working with both law enforcement and outside cybersecurity firms.

This isn’t the first time HBO has dealt with leaks.

In 2015, the first four episodes of season five of Game of Thrones hit the Internet ahead of the season premiere. Those leaks originated from early screenings sent to reviewers, prompting the network to end its practice of sending episodes to reviewers in advance.

Game of Throne has been the most pirated show on TV for several years running. It’s so large and important to HBO that the network even forces the show’s stars to use two-factor authentication on their e-mail accounts.

The season seven finale is set to air on August 27.