More than 100,000 users pirated the episode within hours of it being uploaded from BitTorrent sites, according to TorrentFreak.
Producer 20th Century Fox said its anti-piracy unit was addressing the issue.
Homeland is due to return to US TV screens on 29 September.
It is expected to be shown in the UK at the beginning of October.
Deadline reported preview copies of the episode were distributed to press at a Television Critics Association event last month.
However, it is unlikely to be the source of the leak as the pirated copy is a workprint - an unfinished copy missing visual effects and the opening credits.
The last high-profile workprint to be leaked was in 2009, when an unfinished copy of Hugh Jackman film The Wolverine appeared on torrent sites a month ahead of its release.
Although the source of the leak was never identified, New Yorker Gilberto Sanchez was eventually arrested and sentenced in 2011 to a year in prison for uploading a copy of the film to a file sharing website.
Homeland has been a hit around the world since it began in 2011.
It has been nominated for 11 awards at this year's Emmys, including outstanding drama series and lead actor and actress nods for Damian Lewis and Claire Danes.
source: www.bbc.co.uk |
