The full scope of the recently-discovered Spectre and Meltdown vulnerabilities is still being determined. It may be that hardware or firmware changes will be necessary to truly remove the danger. However, it’s still possible that operating system and application updates can mitigate the risk sufficiently for most purposes.

Once Microsoft demonstrated that the new timing-based attacks could be used in JavaScript code on a malicious web page to read data from other web sites, the folks at Mozilla decided to make that more difficult to accomplish in Firefox. Since the vulnerabilities are timing-dependent, Mozilla reduced the accuracy of several time sources within Firefox that could be used in Spectre and Meltdown based exploits.

The result is Firefox 57.0.4, released on January 4. It’s difficult to know just how helpful these changes will be, but if you use Firefox, you should install this update.