Any website using CSR only can't have a RCE because the code runs on the client. Any code capable of RSC that runs server and client side may be vulnerable.

From what I've seen, the exploit is a special request from a client that functionally lets you exec anything you want (via Function's constructor). If your server is unpatched and recognizes the request, it may be (likely is) vulnerable.

I'm sure we'll get more details over time and tools to manually check if a site is compromised.