Google has stopped rolling out the flawed updater while it works on a permanent fix. In the meantime, those with affected systems can boot into macOS' recovery mode and use a series of Terminal commands to both delete the offending updater and restore the damaged section of the file system. This only affects people who've deliberately turned off SIP or use an operating system before macOS Mavericks, so you'll likely know if you're affected.

Update 9/25 4:10PM ET: Avid says Media Composer doesn't require turning off SIP, but did confirm that it's Chrome's updater causing the problem.