Hooray! Today is the Firefox release day. The new version Firefox 87 is getting released right now and we already grabbed it from Mozilla's FTP servers and installed it in our online browser cloud. It's ready for you to start testing!

Firefox 87 About Dialog

Try Browserling on Firefox 87 now!

New in Firefox 87

  • Improved SmartBlock - You'll encounter less breakage in Private Browsing Mode with the Strict Enhanced Tracking Protection turned on in SmartBlock, which provides stand-in scripts so that websites load properly.
  • Trimmed HTTP Referrer - To further protect your privacy, Firefox 87's new default HTTP Referrer policy will trim path and query string information from referrer headers to prevent sites from accidentally leaking sensitive user data.
  • Highlight All in Find - The "Highlight All" feature on the "Find in Page" now displays tick marks alongside your scrollbar that correspond to the location of matches found on that page.
  • Screen Reader on MacOS - Firefox 87 now has full support for macOS built-in screen reader called VoiceOver.
  • Silesian Locale - Firefox 87 adds the new Silesian (szl) language locale.

Changes in Firefox 87

  • To prevent user data loss when filling out forms, Firefox 87 disables the Backspace key as a navigation shortcut for the back navigation button. To re-enable the Backspace keyboard shortcut, you can change the about:config preference browser.backspace_action to 0. You can also use the recommended Alt + Left arrow (Command + Left arrow on Mac) shortcut instead.
  • Firefox 87 removes items from the Library menu that aren't used often or have other access points in the browser: Synced tabs, Recent highlights, and Pocket list.
  • Firefox 87 simplifies the Help menu by reducing redundant items, such as those that point to Firefox support pages that can also be accessed via the Get Help item.
  • The "View Image Info" menu label in the image context menu has been removed.

Accessibility Fixes in Firefox 87

  • Video controls now have visible focus styling and video and audio controls are now keyboard navigable.
  • HTML <meter> is now spoken by screen readers.
  • Firefox now sets a useful initial focus in Add-ons Manager.
  • Firefox will now fire a name/description change event when aria-labelledby/describedby content changes.

Developer's Corner

Firefox 87 brings many changes and improvements to web developers:

  • Firefox 87 greatly simplifies the Web Developer menu. You can now quickly go to Application Menu followed by Web Developer followed by Web Developer Tools to access Inspector, Web Console, Debugger, Network Style Error, Performance, Storage Inspector, Accessibility, and Application.
  • The Page Inspector can now be used to simulate prefers-color-scheme media queries, without having to change the operating system to light or dark mode.
  • The Page Inspector to toggle the :target pseudo-class for the currently selected element in addition to the pseudo-classes that were previously supported: :hover, :active and :focus, :focus-within, :focus-visible, and :visited.
  • More Page Inspector improvements and bug fixes related to inactive CSS rules: the table-layout property is now marked as inactive for non-table elements, the scroll-padding properties (shorthand and longhand) are now marked as inactive for non-scrollable elements, the text-overflow property was previously incorrectly marked as inactive for some overflow values.

CSS Changes

  • The <link> element is no longer matched by :link, :visited, or :any-link. This aligns the behavior in Firefox to existing behavior in Chrome.

Network/HTTP Changes

  • Content-Length HTTP header has been added to the list of CORS safe-listed response headers.

DOM API Changes

  • The beforeinput event and getTargetRanges() method are now enabled by default.

Changes for add-on developers

  • Permission "nativeMessaging" is now optional.

Changes in Firefox 87 for Android

  • The new default HTTP Referrer policy will trim path and query string information from referrer headers to prevent sites from accidentally leaking sensitive user data.
  • Sharing an image now shares the image itself instead of its URL.
  • Sites that have only been visited once are no longer automatically added as Top Sites on the home screen.
  • WebRender is rolling out to more devices, with the following mobile GPUs now supported: Adreno 505, Adreno 506, and Mali-T.

Security Fixes in Firefox 87

  • CVE-2021-23981: Texture upload into an unbound backing buffer resulted in an out-of-bounds read.
  • CVE-2021-23982: Internal network hosts could have been probed by a malicious webpage.
  • CVE-2021-23983: Transitions for invalid ::marker properties resulted in memory corruption.
  • CVE-2021-23984: Malicious extensions could have spoofed popup information.
  • CVE-2021-23985: Devtools remote debugging feature could have been enabled without indication to the user.
  • CVE-2021-23986: A malicious extension could have performed credential-less same-origin policy violations.
  • CVE-2021-23987, 23988: Memory safety bugs fixed in Firefox 87.

Have fun cross-browser testing in Firefox 87!