HBO acknowledged on Wednesday that episode six of the seventh season of Game of Thrones, which is set to air on Sunday, leaked online for a brief period on Wednesday. In a statement to tech site Mashable, an HBO spokesperson said that the episode was “accidentally posted” to HBO Nordic and HBO España before it was taken down. HBO said that the episode was mistakenly published by an unidentified “third-party vendor” and quickly removed it.

Although the episode was up for a very short period of time, fast-acting Internet users quickly captured screen shots and published videos online. Some users even streamed the episode live over social networks, according to Mashable. However, HBO moved swiftly to have those clips removed, and social media sites approved its request.

Get Data Sheet, Fortune’s technology newsletter

What HBO can’t do, however, is stop the flow of spoilers that have since swept across the Internet. Those who saw at least some of the episode have shared details on social media sites, making it awfully dangerous out there for those who want to be surprised when the full episode airs on Sunday.

Worst of all for HBO, this is just the latest in a string of bad news for the company and one of its top franchises.

Earlier this month, hackers leaked episode four in the current season after they obtained data from HBO servers. Four people were arrested in India on Tuesday on suspicion they might have leaked the episode.

In a statement to Mashable, HBO confirmed the most recent leak was a mistake and not the result of the “recent cyber incident.”