The vulnerability, that only impacts specific versions of Windows 10 and Windows Server, was found in the Microsoft Server Message Block 3.1.1 and was leaked  during last month's Patch Tuesday after being accidentally published by a number of security vendors part of Microsoft Active Protections Program.
Researcher demoed a PoC RCE exploit, published a paper  with all the technical details, and shared a video demo:
Should I be worried?
Mildly! Ricerca Security has decided not to share their exploit to avoid having it fall in the wrong hands:
We have decided to make our PoC exclusively available to our customers to avoid abuse by script kiddies or cybercriminals
However, if you haven't yet patched your systems against CVE-2020-0796, you should do it as soon as possible and, if you can't update at the moment, Microsoft's recommends disabling SMBv3 compression: please refer to my previous post  for technical details.