Firefox 121 supports AV1, improves PDF viewer

Firefox 121 stable is now available for download. It includes support for AV1 with hardware acceleration, a recycle bin icon in PDF viewer to quickly remove annotations, and fixes 27 vulnerabilities. In addition, Firefox ESR has reached version 115.6.0, and Firefox 122 enters Beta.

Firefox 121

What's new in Firefox 121

  • In the Browsing section of the settings, version 121 adds a new option to enable the underlining of links, regardless of the website's CSS settings. This feature can be especially useful for individuals who have difficulty perceiving colors.
  • The PDF viewer now includes a floating trash can button, allowing users to easily delete drawings, text, and images that were added while editing a PDF.Firefox 121 Pdf Image Button
  • On the Windows platform, users can now install the AV1 Video Extension package, which enables hardware acceleration for video decoding in the AV1 format. This enhancement improves video playback performance.
  • For macOS users, the latest update introduces support for control through voice commands. This feature offers more accessibility options for navigating and interacting with the browser.
  • On Linux, the browser now uses the Wayland composite server instead of XWayland by default. The change solves various issues with the touchpad, gesture support on touch screens, and DPI setting for each monitor in Wayland-based environments.
  • The update also introduces support for lazy loading iframe blocks. With this feature, content outside the viewable area of a webpage will not load until the user scrolls to it. This helps optimize memory consumption, reduce web traffic, and improves the speed of page loading.

In addition to these new features and bug fixes, Firefox 121 also addresses 27 vulnerabilities. Among them, 13 are considered high-risk, including memory-related issues like buffer overflows and accessing freed memory areas. These vulnerabilities could potentially be exploited by attackers through specially crafted web pages. Another significant vulnerability (CVE-2023-6135) addressed in this update involves the susceptibility of the NSS library to the "Minerva" attack, which allows unauthorized parties to recreate private encryption keys through data analysis.


Download Firefox 121

You can update to the latest version of Firefox by going to the About Firefox section of the browser's menu.

Linux users should use the OS' package manager to get the latest version available for the distro. E.g. in Ubuntu/Mint with the official mozillateam PPA connected, you can run the apt update && apt install firefox command in a root terminal.

Alternatively, you can download the installers here:  There, pick the browser that matches your operating system, language and platform. Files in there are organized into subfolders by a platform, UI language, and include full (offline) installers. The official release notes are here:

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Author: Sergey Tkachenko

Sergey Tkachenko is a software developer who started Winaero back in 2011. On this blog, Sergey is writing about everything connected to Microsoft, Windows and popular software. Follow him on Telegram, Twitter, and YouTube.

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