Given that the Kardashians are such a big family and they're all famous, there are a lot of people coming in and out of each of their lives who could get close to one family member and sell stories about the others.
In this sneak peek from this week's Kourtney and Khloe Take the Hamptons, Kourtney Kardashian says that someone has been selling stories about their family to the media "for years."
The prime suspect is Kim Kardashian's BFF Jonathan Cheban, who Kourtney explains has a lot of contacts with the media (he used to be a publicist) and Kourtney is worried because Kim tells him everything.
Our guess is that it wasn't Jonathan because this was filmed awhile ago and he's still been popping up in pictures with the famous fam since the season wrapped.
Who do you guys think is the Kardashian leak?
This episode airs Sunday, November 30 at 9pm ET/PT on E!