Valve certainly already knows about it, because the issue has gone viral. In fact, there is a command that gives players a wallhack.
It probably wasn’t supposed to work that way, but at this point it does. That’s what the beta is for, after all, to catch this kind of thing and fix it. It’s a good thing someone figured it out at a time when CS2 isn’t yet available to everyone.
Anyway, streamers took advantage of it, of course disabling the feature after a while. Few people believed that it would actually work, and everyone was aware that it was unfair to use it.
Legal WH in CS2
Just use a simple command that provides a green border around your opponent. This works exactly like a legal wallhack.
Valve certainly has enough information about this already and all that remains is to wait for a hotfix. At this point, it can ruin the gameplay, since a lot of people are finding out about it and matches resemble duels of the mind more than of skill, i.e. who will peek first, who will get baited, etc. This is because everyone knows where their opponents are.