If you don't have the most recent version of the popular Mozilla Firefox Web browser, you need to get it immediately. It turns out that a hacker had full access to some very critical security flaws for nearly two years.
The hacker had access to Mozilla's database of vulnerabilities with Firefox, called Bugzilla. Some of those flaws were fixed, but some weren't.
The hacker got into Bugzilla by using another person's password, which had been used at another site that was hit with a data breach. This is just another example of why you should never use the same password twice. Read my tips on creating safe passwords by clicking here.
Mozilla has taken a number of steps to restore Firefox's security, but you need to ensure you have the latest version. To find out, open Firefox and go to https://www.mozilla.org/firefox/. Your browser will tell you if you have the latest version, and if not, you'll be prompted to install it.