TL;DR there was a backdoor found in the XZ program. All major distros have been updated but it is recommended that you do a fresh install on systems that are exposed to the internet and that had the bad version of the program. Only upstream distros were affected.
Ars Technica sounds like a weirdo to me these days. Loves to attack big techs (although understandable), now adds this to their description of Arch.