Presumably you mean the most recent common ancestor of humans and all modern apes (since the most recent common ancestor would itself be classified as an ape, and since the most recent common ancestor of humans with chimpanzees is more recent than the most recent common ancestor of humans - and chimps - with orangutans).
The answer is that we probably have not found it but there's no way to tell for sure. Most species - especially land vertebrates - have left no fossils whatsoever. And it is impossible to tell for certain whether a fossil actually is in the direct line of ancestry rather than simply an offshoot except in very special cases.
I imagine that you actually want the last common ancestor of humans and chimpanzees. Although there's no fossil I can point to and say that it is that, there is
Orrorin tugenensis which likely belongs on the human side of the divide, and dates to shortly after the lineages diverged.
So, we don't have any expectation of finding "the common ancestor". What we expect to find is a sampling of species that includes - maybe - some common ancestors and a lot more near relatives, like
Orrorin. And that's what we do find.