Kurill Prime

From Memory Alpha, the free Star Trek reference.

Kurill Prime is a planet in the Gamma Quadrant. Eris claimed Kurill Prime was the homeworld of the Vorta, which was conquered by the Dominion in 2370. However, Eris was in fact a Dominion spy and her story was a fabrication. (DS9: "The Jem'Hadar")

There's no incontrovertible evidence that Kurill Prime is actually the Vorta homeworld; given that Eris was lying about everything else she could have easily been lying about this as well. Then again, it is possible that Kurill Prime is the planet where the proto-Vorta were uplifted by the Founders, as Weyoun described in "Treachery, Faith and the Great River".