It is time to update the Chrome desktop browser on Mac, Windows, and Linux once again to fix a dangerous "zero-day" flaw that is already being used to attack computer users.

Details of the zero-day flaw are still largely unknown. According to a post on Google's Chrome blog yesterday (July 15), the flaw is related to a "type confusion in V8," the JavaScript rendering engine used in Chrome, and "Google is working with CVE-2021-30563 (the flaw's catalog number) and is aware of reports that there are exploits against it in the wild."

According to Bleeping Computer, this is the eighth zero-day flaw patched into Chrome this year.

Earlier this week, Google researchers announced that a "for-profit surveillance firm" had developed and sold exploits against two older Chrome zero-day exploits to national intelligence agencies. A day later, Microsoft and the Citizen Lab at the University of Toronto identified the company as the Israeli spyware company Candiru, which said its customers were in the Middle East and the former Soviet Union.

Seven other flaws were fixed in Chrome 91.0.4472.164, two of which are related to the V8 vulnerability. Most of the flaws are classified as "high" in severity, indicating that remote code execution (hacking via the Internet) is possible.

To update Chrome on Windows and Mac, try quitting and restarting the browser. If that does not work, click on the three vertical dots in the upper right corner of the browser window. Scroll down, mouse over Help, and click About Google Chrome.

A new tab will open, displaying your version of Chrome (version 91.0.4472.164). Then simply restart your browser.

Most Linux distributions update Chrome as part of their rolling update schedule, but you may have to tweak your software repository settings to get the builds to the Google update servers.

Other Chrome distributions will update Chrome as part of their rolling update schedule.

Updates for other Chromium-based browsers are similar: in Brave, click on the three vertical lines in the upper right corner, scroll down, and click "About Brave" in the Settings menu; in Microsoft Edge, click on the three vertical dots in the upper right corner Click, scroll down, mouse over "Help and Feedback," and click "About Microsoft Edge."

In Opera and Vivaldi, click the browser icon in the upper left corner, scroll down, mouse over "Help" and select "About".

As of this writing Friday (July 16) at noon (New York), none of these other Chromium-based browsers have been updated to the latest version.

Brave uses the same version number system as Chrome and Chromium; Opera and Vivaldi use their own systems, but Chromium's build number appears under User Agent on the About page. In Edge, typing "edge://version/" in the address bar and pressing Enter or Return will display the Chromium build number under User Agent.

There is a list of the latest updates for Chrome, so check to see if your browser is up-to-date.