A couple of important points here. What was theoretically broken was the audio alternative option in reCaptcha. Bad but not as bad as it could be. What is probably worse, though, is that an exploit has been previously published of this same option, in fact using Google’s own voice processing API’s against it. Nothing about how Google can or will shore up this vulnerability.
Google’s reCaptcha service has been cracked by researchers who devised an automated attack called unCaptcha that can break the service with 85 percent accuracy.