Hot on the heels of an emergency update to Google's Chrome web browser comes yet another security update for billions of users across multiple operating system platforms. This time, the update urgency remains the same, but the number of vulnerabilities does not: four high-rated vulnerabilities have been confirmed by Google; here's what you need to know and do.

Google has confirmed that the Chrome web browser is being updated for security reasons, an update that will roll out in the coming days and weeks. The reason? A total of four high-rated security vulnerabilities which between them have earned the security researchers who discovered them a whopping $75,000 in hacker bounties.

The four vulnerabilities that Google has confirmed are:

"Access to bug details and links may be kept restricted until a majority of users are updated with a fix," Prudhvikumar Bommana from the Google Chrome security team said, "We will also retain restrictions if the bug exists in a third-party library that other projects similarly depend on, but haven't yet fixed."

The more than 3 billion users of Google Chrome who are potentially impacted by these security vulnerabilities need to make sure that they are protected as soon as possible. If you are in that number, and the chances are high that you are, then you need to kickstart the updating process and then activate the updated browser itself to enable the protection to be in place. Google does automatically update the Chrome browser, but this relies on users restarting the client, which lots of people with lots of open tabs don't like doing. So, please follow these steps now:

Head for the Help|About option in your Google Chrome menu to kickstart an automatic security update download.

Restart your Google Chrome browser after the update has been installed, or it will not activate, and you will still be vulnerable to attack.

Repeat step one to ensure that the Google Chrome update is installed and activated, and that you are now fully protected against these latest security threats.