A common ancestor species of what? Between Humans and Chimpanzees? Or between their ancestor species and apes in general? The answer to both is yes - lots of them.
If you want a common ancestor species between humans and chimps, its not difficult to find. It's right there in the cladogram of the human ancestral tree. The hominini tribe - including Australopithecus, Paranthropus and Ardipithecus, among others - has a lot of fossil evidence of Human-Chimp common evolutionary ancestry.
The last common ancestor species, no. We don't know the specific ancestor species between Chimpanzees (Pan) and Human ancestors (hominids). There may actually be no such thing - evolution being what it is**. But, we're looking for candidate species in the fossil record. And, we've got a pretty good idea where and when the separation occured.
**It is advisable to know that evolution is not a straight forward process and speciation events in large, social mammal species are particularly drawn out - as I mentioned, the genetic evidence is that there were multiple branchings, loops and hybridisation events occurring in the separation of the species that eventually led to Chimpanzees and Humans. It's a VERY complicated, and as yet not fully resolved, picture.