Most users will auto-update & it’s beneficial to stay as up-to-date as possible on browsers, O/S, and all other software

Firefox 93.0, See All New Features, Updates and Fixes (

Mozilla Releases Security Updates for Firefox and Firefox ESR | CISA

Security Vulnerabilities fixed in Firefox 93 — Mozilla

Mozilla has released security updates to address vulnerabilities in Firefox and Firefox ESR . An attacker could exploit some of these vulnerabilities to take control of an affected system.  CISA encourages users and administrators to review the Mozilla security advisories for Firefox 93Firefox ESR 78.15, and Firefox ESR 91.2.


  • Firefox now supports the new AVIF image format, which is based on the modern and royalty free AV1 video codec. It offers significant bandwidth savings for sites compared to existing image formats. It also supports transparency and other advanced features.
  • Firefox PDF viewer now supports filling more forms (XFA-based forms, used by multiple governments and banks). Learn more.
  • When available system memory is critically low, Firefox on Windows will automatically unload tabs based on their last access time, memory usage, and other attributes. This should help reduce Firefox out-of-memory crashes. Switching to an unloaded tab automatically reloads it.
  • To prevent session loss for macOS users who are running Firefox from a mounted .dmg file, they’ll now be prompted to finish installation. This permission prompt only appears the first time these users run Firefox on their computer.
  • Firefox now blocks downloads that rely on insecure connections, protecting against potentially malicious or unsafe downloads. Learn more and see where to find downloads in Firefox.
  • Improved web compatibility for privacy protections with SmartBlock 3.0. Learn more
  • Introducing a new referrer tracking protection in Strict Tracking Protection and Private Browsing. Learn more
  • Introducing Firefox Suggest, a faster way to navigate the web. Learn more about the experience and locale-specific features