It has been a frantic week for Apple, Google and Microsoft as they have tried to deal with a serious CPU vulnerability in modern processors from Intel, ARM and AMD. The security issue, which could allow for system memory to be read which could give access to passwords and other sensitive information. The significance of this issue is that it requires an OS level update to fix.
For Google and Chrome OS, the fix is already out. The Chrome 63 train for Chrome OS was released on December 15th and part of that update was fixing this issue. The issue does not impact Chrome OS devices running ARM processors. This is good news as it means a wide swatch of Chromebooks are already protected.
That said, not everyone has seen the Chrome 63 update for their Chromebook. You can still protect yourself however. There is a flag that you can set that will enable Site Isolation. This trick, by the way, also works on the Chrome browser for Android, Linux, Windows and Mac. The flag you need to enable is chrome://flags#enable-site-per-process. You need to enable it and then restart Chrome.
This flag is enabled by default in Chrome 63 so the flag only needs to be enabled on Chrome 62 and older on Chrome OS.
If you are curious, Chrome 64 will address this issue on the desktop browser for desktop platforms as well as Chrome for Android.