If you are using Mozilla's Firefox then its time to update your Firefox immediately. As Mozilla says, a critical bug ( CVE-2019-11707: Type confusion in Array.pop ) has been reported by Samuel GroB of Google project zero. And this bug can be used to exploit your system.
Hackers can use this bug to inject code when you visit a malicious site, Mozilla said in a statement.
So, if you are using Firefox, kindly update to latest version ( Firefox 67.0.3 and Firefox ESR 60.7.1) immediately.
Here are the download links, if you need..
You can read the information about this bug on official site.