Firefox 95 for Windows and Mac introduces RLBox, a new sandbox technology

Mozilla has released the latest version of Firefox, Firefox 95 for Windows and macOS. It is now available to all users on both platforms.

On both macOS and Windows, Mozilla “improved page loading performance by speculatively pre-compiling JavaScript.”There is also a way to move the PIP toggle button to the opposite side of the video on both platforms, as well as a number of fixes.

But aside from these optimizations and tweaks, Firefox 95’s best improvements are related to security, as RLBox is now enabled on all platforms. Mozilla has published a detailed blog post explaining what RLBox is and how it works, but the summary is that it is a new sandboxing technique that isolates potentially problematic code in WebAssembly and protects users from threats.

Bobby Holley of Mozilla writes that RLBox goes beyond what a process-based sandbox provides, and that it will be applied differently in the future:

RLBox is a big win for us on several fronts: it protects our users from random defects as well as supply chain attacks, and reduces the need for scrambling when such issues are discovered upstream. So we intend to continue to apply to more components in the future.

Firefox 95 follows the November 2 release of Firefox 94, which, among other things, added new color themes, introduced site isolation (which is now enabled by default for all Firefox 95 users), made changes to the way updates are delivered, and made several optimizations for The OS, for example, improved the performance of WebGL under Linux.