Mozilla Firefox Version 91.0 Released With Security Updates

   Mozilla sent Firefox Version 91.0 to the release channel today.  The update includes eleven security updates of which eight (8) are rated high, two (2) moderate, and one (1) rated low.

Firefox ESR was updated to Version 78.13.

High

• CVE-2021-29986: Race condition when resolving DNS names could have led to memory corruption 

• CVE-2021-29981: Live range splitting could have led to conflicting assignments in the JIT

• CVE-2021-29988: Memory corruption as a result of incorrect style treatment 

• CVE-2021-29983: Firefox for Android could get stuck in fullscreen mode

• CVE-2021-29984: Incorrect instruction reordering during JIT optimization 

• CVE-2021-29980: Uninitialized memory in a canvas object could have led to memory corruption 

• CVE-2021-29989: Memory safety bugs fixed in Firefox 91 and Firefox ESR 78.13 

• CVE-2021-29990: Memory safety bugs fixed in Firefox 91

Moderate

• CVE-2021-29987: Users could have been tricked into accepting unwanted permissions on Linux
• CVE-2021-29985: Use-after-free media channels

Low

• CVE-2021-29982: Single bit data leak due to incorrect JIT optimization and type confusion

New

• Building on Total Cookie Protection, we've added a more comprehensive logic for clearing cookies that prevents hidden data leaks and makes it easy for users to understand which websites are storing local information. Learn more
• Firefox now supports logging into Microsoft, work, and school accounts using Windows single sign-on. Learn moreThe simplify page when printing feature is back! When printing, under More settings > Format select the Simplified option when available to get a clutter-free page. Learn more
• HTTPS-First Policy: Firefox Private Browsing windows now attempt to make all connections to websites secure, and fall back to insecure connections only when websites do not support it. Learn more
• We've added a new locale: Scots (sco)
• The address bar now provides Switch to Tab results also in Private Browsing windows.
• Firefox now automatically enables High Contrast Mode when "Increase Contrast" is checked on MacOS
• Firefox now does catch-up paints for almost all user interactions, enabling a 10-20% improvement in response time to most user interactions.

Update 

To get the update now, select "Help" from the Firefox menu, then pick "About Firefox."  Mac users need to select "About Firefox" from the Firefox menu. If you do not use the English language version, Fully Localized Versions are available for download.

References

• Security Updates
• Release Notes
• Rapid Release Calendar