The bug used by Tavis Ormandy was patched in August via Windows Update, but the CTF protocol is vulnerable by design. Here is why:
"Any application, any user - even sandboxed processes - can connect to any CTF session. Clients are expected to report their thread id, process id and HWND, but there is no authentication involved and you can simply lie.
"So you could connect to another user's active session and take over any application, or wait for an Administrator to login and compromise their session."
Of course, the system has to be first compromised by another kind of exploit or malware.