While the advice below is specific to an issue with Google Chrome on March 21, 2019, it is an important general practice that everyone should follow.
"If you are running Google Chrome and its version is below 72.0.3626.121, your computer could be exploited without your knowledge. While it’s true that Chrome features an automatic update component, in order for the patch to be installed you must restart your browser."
Considering how many users keep Chrome and all their tabs opened for days or even weeks without ever restarting the browser, the security impact is real.
In the meantime, if you haven’t done so yet, you should update and relaunch Chrome; and don’t worry about your tabs, they will come right back.
Along with restarting your web browser, it is also important for your computer's security to restart the computer at least once a week.