If that would happen, The worry I would have is of all the sensitive Government servers from all over the world which might be then exploited and the amount of damage which can be caused silently by such a threat actor or something like AWS/GCP/these massive hyperscalers which are also used by the governments around the globe at times.

The possibilities within a good threat could be catastrophic if we assume so, and if we assume nation-states to be interested in sponsoring hacking attacks (which many nations already do) to attack enemy nations/gain leverage. We are looking at damage within Trillions at that point.

But I would assume that Linux might be safe for now, it might be the most looked at code and its definitely something safe.

LLVM might be a bit more interesting as it might go a little unnoticed but hopefully people who are working at LLVM are well funded/have enough funding to take a look at everything carefully to not have such a slip up.