The Firefox/Mozilla Thread

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ff v81.0.2

13. october 2020

Fixed

• Fixed an incompatibility with Twitter.com manifesting itself with the intermittent display of a network protocol violation error page

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ff v82.0

20. october 2020

New

• With this release, Firefox introduces a number of improvements that make watching videos more delightful:

  • the Picture-In-Picture button has a new look and position, making it easier for you to find and use the feature.
  • Picture-In-Picture now has a keyboard shortcut for Mac users (Option + Command + Shift + Right bracket) that works before you start playing the video.
  • For Windows users, Firefox now uses DirectComposition for hardware decoded video, which will improve CPU and GPU usage during video playback, improving battery life.

• Firefox is faster than ever with improved performance on both page loads and start up time:

  • Websites that use flexbox-based layouts load 20% faster than before;
  • Restoring a session is 17% quicker, meaning you can more quickly pick up where you left off;
  • For Windows users, opening new windows got quicker by 10%.

• You can now explore new articles when you save a webpage to Pocket from the Firefox toolbar.

• WebRender continues to roll out to more Firefox users on Windows.

Fixed

• Screen reader features which report paragraphs now correctly report paragraphs in Firefox instead of lines.

• Various security fixes

Changed

• Credit card auto-fill is now more accessible with the card type, and the card number in the card editor now available to screen readers.

• Printing dialog errors for invalid form entries are now reported to screen readers.

Developer

Developer Information

• MediaSession API has been enabled by default which allows web authors to provide custom behaviors for standard media playback interactions, giving them more options than ever.

• DevTools now shows server side events in the Network panel. This allows a server to send new data to a web page at any time allowing developers to see events they previously couldn't and help with lower-level troubleshooting.

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ff v78.4.0 esr

20. october 2020

Fixed

• Various stability, functionality, and security fixes

Quote

Security Vulnerabilities fixed in Firefox ESR 78.4

Announced October 20, 2020

Impact high

Products Firefox ESR

Fixed in

• Firefox ESR 78.4

#CVE-2020-15969: Use-after-free in usersctp

Reporter Mark Wodrich of Google

Impact high

Description

A use-after-free bug in the usersctp library was reported upstream. We assume this could have led to memory corruption and a potentially exploitable crash.

References

• Bug 1666570
• [sctplab] upstream usrsctp fix

#CVE-2020-15683: Memory safety bugs fixed in Firefox 82 and Firefox ESR 78.4

Reporter Mozilla developers and community

Impact high

Description

Mozilla developers and community members Jason Kratzer, Simon Giesecke, Philipp, and Christian Holler reported memory safety bugs present in Firefox 81 and Firefox ESR 78.3. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.

References

• Memory safety bugs fixed in Firefox 82 and Firefox ESR 78.4

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ff v82.0.1

27. october 2020

Fixed

• Avoid an unnecessary prompt to reboot when using the full installer on Windows (bug 1671715)

• Restored the ability to print on paper whose width or height is larger than 100 inches, e.g. for receipts (bug 1672370)

• Fixed printing of documents with margins of zero, e.g. some PDFs (bug 1672529)

• Fixed handling of the WebDriver:ClickElement command in the marionette testing framework (bug 1666755)

• Stability fix (bug 1660539)

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ff v82.0.2

28. october 2020

Fixed

• Fixed duplication of WebSocket messages in certain cases (bug 1673340)

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ff v83.0

17. november 2020

New

• Firefox keeps getting faster as a result of significant updates to SpiderMonkey, our JavaScript engine, you will now experience improved page load performance by up to 15%, page responsiveness by up to 12%, and reduced memory usage by up to 8%. We have replaced part of the JavaScript engine that helps to compile and display websites for you, improving security and maintainability of the engine at the same time.

• Firefox introduces HTTPS-Only Mode. When enabled, this new mode ensures that every connection Firefox makes to the web is secure and alerts you when a secure connection is not available. You can enable it in Firefox Preferences.

• Pinch zooming will now be supported for our users with Windows touchscreen devices and touchpads on Mac devices. Firefox users may now use pinch to zoom on touch-capable devices to zoom in and out of webpages.

• Picture-in-Picture now supports keyboard shortcuts for fast forwarding and rewinding videos: use the arrow keys to move forward and back 15 seconds, along with volume controls. For a list of supported commands see Support Mozilla

• When you are presenting your screen on a video conference in Firefox, you will see our improved user interface that makes it clearer which devices or displays are being shared.

• We’ve improved functionality and design for a number of Firefox search features:

  • Selecting a search engine at the bottom of the search panel now enters search mode for that engine, allowing you to see suggestions (if available) for your search terms. The old behavior (immediately performing a search) is available with a shift-click.
  • When Firefox autocompletes the URL of one of your search engines, you can now search with that engine directly in the address bar by selecting the shortcut in the address bar results.
  • We’ve added buttons at the bottom of the search panel to allow you to search your bookmarks, open tabs, and history.

• Firefox supports AcroForm, which will allow you to fill in, print, and save supported PDF forms and the PDF viewer also has a new fresh look.

• Our users in India on the English build of Firefox will now see Pocket recommendations in their new tab featuring some of the best stories on the web. If you don’t see them, you can turn on Pocket articles in your new tab by following these steps.

• For the recently released Apple devices built with Apple Silicon CPUs, you can use Firefox 83 and future releases without any change. This release (83) will support emulation under Apple’s Rosetta 2 that ships with macOS Big Sur. We are working toward Firefox being natively-compiled for these CPUs in a future release.

• This is a major release for WebRender as we roll out to more Firefox users on Windows 7 and 8 as well as on macOS 10.12 to 10.15.

Fixed

• This release also includes a number of accessibility fixes:

  • Screen reader features which report paragraphs now correctly report paragraphs instead of lines in Google Docs
  • When reading by word using a screen reader, words are now correctly reported when there is punctuation nearby
  • The arrow keys now work correctly after tabbing in the picture-in-picture window

• For users on macOS restoring a session with minimized windows, Firefox now uses much less power and you should see much longer battery life.

• Various security fixes

Enterprise

• Enterprise Information

Developer

Developer Information

• Developers can use the scroll badge in the Page Inspector to Debug scrollable overflow. Selecting the badge highlights elements that are causing overflow and marks them with the overflow badge

Web Platform

• This release adds support for conic gradients in CSS, helping colors to smoothly transition as you spin around the center, rather than as you progress outward from the center.

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ff 78.5.0 esr

17. november 2020

Fixed

• Various stability, functionality, and security fixes

Quote

Security Vulnerabilities fixed in Firefox ESR 78.5

Announced November 17, 2020

Impact high

Products Firefox ESR

Fixed in

• Firefox ESR 78.5

#CVE-2020-26951: Parsing mismatches could confuse and bypass security sanitizer for chrome privileged code

Reporter Irvan Kurniawan (@sourc7)

Impact high

Description

A parsing and event loading mismatch in Firefox's SVG code could have allowed load events to fire, even after sanitization. An attacker already capable of exploiting an XSS vulnerability in privileged internal pages could have used this attack to bypass our built-in sanitizer.

References

• Bug 1667113

#CVE-2020-16012: Variable time processing of cross-origin images during drawImage calls

Reporter Aleksejs Popovs

Impact moderate

Description

When drawing a transparent image on top of an unknown cross-origin image, the Skia library drawImage function took a variable amount of time depending on the content of the underlying image. This resulted in potential cross-origin information exposure of image content through timing side-channel attacks.

References

• Bug 1642028

#CVE-2020-26953: Fullscreen could be enabled without displaying the security UI

Reporter Abdulrahman Alqabandi of Microsoft Browser Vulnerability Research

Impact moderate

Description

It was possible to cause the browser to enter fullscreen mode without displaying the security UI; thus making it possible to attempt a phishing attack or otherwise confuse the user.

References

• Bug 1656741

#CVE-2020-26956: XSS through paste (manual and clipboard API)

Reporter Irvan Kurniawan (@sourc7)

Impact moderate

Description

In some cases, removing HTML elements during sanitization would keep existing SVG event handlers and therefore lead to XSS.

References

• Bug 1666300

#CVE-2020-26958: Requests intercepted through ServiceWorkers lacked MIME type restrictions

Reporter Moti Harmats

Impact moderate

Description

Firefox did not block execution of scripts with incorrect MIME types when the response was intercepted and cached through a ServiceWorker. This could lead to a cross-site script inclusion vulnerability, or a Content Security Policy bypass.

References

• Bug 1669355

#CVE-2020-26959: Use-after-free in WebRequestService

Reporter Bharadwaj Machiraju

Impact moderate

Description

During browser shutdown, reference decrementing could have occured on a previously freed object, resulting in a use-after-free, memory corruption, and a potentially exploitable crash.

References

• Bug 1669466

#CVE-2020-26960: Potential use-after-free in uses of nsTArray

Reporter Zijie Zhao

Impact moderate

Description

If the Compact() method was called on an nsTArray, the array could have been reallocated without updating other pointers, leading to a potential use-after-free and exploitable crash.

References

• Bug 1670358

#CVE-2020-15999: Heap buffer overflow in freetype

Reporter Sergei Glazunov of Google Project Zero

Impact moderate

Description

In Freetype, if PNG images were embedded into fonts, the Load_SBit_Png function contained an integer overflow that led to a heap buffer overflow, memory corruption, and an exploitable crash.
Note: While Project Zero did discover instances of this vulnerability being exploited in the wild against Chrome, in Firefox this vulnerability is only triggerable if a rarely-used, hidden preference is toggled, and only affected Linux and Android operating systems. Other operating systems are unaffected; and Linux and Android are unaffected in the default configuration.

References

• Bug 1672223

#CVE-2020-26961: DoH did not filter IPv4 mapped IP Addresses

Reporter Gabriel Corona

Impact moderate

Description

When DNS over HTTPS is in use, it intentionally filters RFC1918 and related IP ranges from the responses as these do not make sense coming from a DoH resolver. However when an IPv4 address was mapped through IPv6, these addresses were erroneously let through, leading to a potential DNS Rebinding attack.

References

• Bug 1672528

#CVE-2020-26965: Software keyboards may have remembered typed passwords

Reporter Makoto Kato

Impact low

Description

Some websites have a feature "Show Password" where clicking a button will change a password field into a textbook field, revealing the typed password. If, when using a software keyboard that remembers user input, a user typed their password and used that feature, the type of the password field was changed, resulting in a keyboard layout change and the possibility for the software keyboard to remember the typed password.

References

• Bug 1661617

#CVE-2020-26966: Single-word search queries were also broadcast to local network

Reporter tiebuchen

Impact low

Description

Searching for a single word from the address bar caused an mDNS request to be sent on the local network searching for a hostname consisting of that string; resulting in an information leak.
Note: This issue only affected Windows operating systems. Other operating systems are unaffected.

References

• Bug 1663571

#CVE-2020-26968: Memory safety bugs fixed in Firefox 83 and Firefox ESR 78.5

Reporter Mozilla developers and community

Impact high

Description

Mozilla developers Steve Fink, Jason Kratzer, Randell Jesup, Christian Holler, and Byron Campen reported memory safety bugs present in Firefox 82 and Firefox ESR 78.4. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.

References

• Memory safety bugs fixed in Firefox 83 and Firefox ESR 78.5

[trium 0]

have forget one :-)

ff v82.0.3

10. nov 2020

Fixed

• Security fix

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ff v84.0

15. dec 2020

New

• Native support for macOS devices built with Apple Silicon CPUs brings dramatic performance improvements over the non-native build that was shipped in Firefox 83: Firefox launches over 2.5 times faster and web apps are now twice as responsive (per the SpeedoMeter 2.0 test). If you are on a new Apple device, follow these steps to upgrade to the latest Firefox.

• WebRender rolls out to MacOS Big Sur, Windows devices with Intel Gen 6 GPUs, and Intel laptops running Windows 7 and 8. Additionally we'll ship an accelerated rendering pipeline for Linux/GNOME/X11 users for the first time, ever!

• Firefox now uses more modern techniques for allocating shared memory on Linux, improving performance and increasing compatibility with Docker.

• Firefox 84 is the final release to support Adobe Flash.

Fixed

• Various security fixes

Enterprise

• Various bug fixes and new policies have been implemented in the latest version of Firefox. You can see more details in the Firefox for Enterprise 84 Release Notes.

Developer

Developer Information

• The Network panel is now able to handle unexpected crashes and render useful debugging details such as a related stack-trace. Users can also easily file a bug report by clicking on the available link to help improve the stability of the tool.
  

• The Accessibility Panel now includes an option for displaying elements in their tabbing order in order to help developers see what elements are focusable when tabbing and in what sequence.

unresolved

• macOS users running on Apple Silicon systems may encounter playback errors on encrypted content if the Rosetta system software is not installed.

• macOS users running Cylance antivirus software may see their Firefox installation get corrupted due to being erroneously flagged as malware.

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ff v78.4.1 esr (belated)

10. nov 2020

Fixed

• Security fix

Quote

Security Vulnerabilities fixed in Firefox 82.0.3, Firefox ESR 78.4.1, and Thunderbird 78.4.2

Announced November 9, 2020

Impact critical

Products Firefox, Firefox ESR, Thunderbird

Fixed in

• Firefox 82.0.3
• Firefox ESR 78.4.1
• Thunderbird 78.4.2

#CVE-2020-26950: Write side effects in MCallGetProperty opcode not accounted for

Reporter 360政企安全漏洞研究院 in Tianfu Cup 2020 International Cybersecurity Contest

Impact critical

Description

In certain circumstances, the MCallGetProperty opcode can be emitted with unmet assumptions resulting in an exploitable use-after-free condition.

References

• Bug 1675905

•  

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ff v78.6.0 esr

15. nov 2020

Fixed

• Various stability, functionality, and security fixes

Quote

Security Vulnerabilities fixed in Firefox ESR 78.6

Announced December 15, 2020

Impact critical

Products Firefox ESR

Fixed in

• Firefox ESR 78.6

#CVE-2020-16042: Operations on a BigInt could have caused uninitialized memory to be exposed

Reporter André Bargull

Impact critical

Description

When a BigInt was right-shifted the backing store was not properly cleared, allowing uninitialized memory to be read.

References

• Bug 1679003

#CVE-2020-26971: Heap buffer overflow in WebGL

Reporter Omair, Abraruddin Khan

Impact high

Description

Certain blit values provided by the user were not properly constrained leading to a heap buffer overflow on some video drivers.

References

• Bug 1663466

#CVE-2020-26973: CSS Sanitizer performed incorrect sanitization

Reporter Kai Engert

Impact high

Description

Certain input to the CSS Sanitizer confused it, resulting in incorrect components being removed. This could have been used as a sanitizer bypass.

References

• Bug 1680084

#CVE-2020-26974: Incorrect cast of StyleGenericFlexBasis resulted in a heap use-after-free

Reporter Pham Bao of VinCSS (Member of Vingroup)

Impact high

Description

When flex-basis was used on a table wrapper, a StyleGenericFlexBasis object could have been incorrectly cast to the wrong type. This resulted in a heap user-after-free, memory corruption, and a potentially exploitable crash.

References

• Bug 1681022

#CVE-2020-26978: Internal network hosts could have been probed by a malicious webpage

Reporter Samy Kamkar, Ben Seri, and Gregory Vishnepolsky

Impact moderate

Description

Using techniques that built on the slipstream research, a malicious webpage could have exposed both an internal network's hosts as well as services running on the user's local machine.

References

• Bug 1677047

#CVE-2020-35111: The proxy.onRequest API did not catch view-source URLs

Reporter Yassine Tioual

Impact low

Description

When an extension with the proxy permission registered to receive <all_urls>, the proxy.onRequest callback was not triggered for view-source URLs. While web content cannot navigate to such URLs, a user opening View Source could have inadvertently leaked their IP address.

References

• Bug 1657916

#CVE-2020-35112: Opening an extension-less download may have inadvertently launched an executable instead

Reporter Samuel Attard via the Chrome Security Team

Impact low

Description

If a user downloaded a file lacking an extension on Windows, and then "Open"-ed it from the downloads panel, if there was an executable file in the downloads directory with the same name but with an executable extension (such as .bat or .exe) that executable would have been launched instead.
Note: This issue only affected Windows operating systems. Other operating systems are unaffected.

References

• Bug 1661365

#CVE-2020-35113: Memory safety bugs fixed in Firefox 84 and Firefox ESR 78.6

Reporter Christian Holler

Impact high

Description

Mozilla developer Christian Holler reported memory safety bugs present in Firefox 83 and Firefox ESR 78.5. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.

References

• Memory safety bugs fixed in Firefox 84 and Firefox ESR 78.6

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ff v84.0.1

22. dec 2020

Fixed

• Fixed problems loading secure websites and crashes for users with certain third-party PKCS11 modules and smartcards installed (bug 1682881).

• Fixed slower than expected performance and flickering on Canvas elements for some Windows users (bug 1683116).

• Fixed a bug causing some Unity JS games to not load on Apple Silicon devices due to improper detection of the OS version (bug 1680516).

• Fixed crashes caused by various third-party antivirus software.

[nukecad 7]

Critical security updates: first offered to Release channel users on January 6, 2021.

84.0.2 Firefox
84.1.3 Firefox for Android
78.6.1 Firefox ESR

https://www.mozilla.org/en-US/security/advisories/mfsa2021-01/

Quote

A malicious peer could have modified a COOKIE-ECHO chunk in a SCTP packet in a way that potentially resulted in a use-after-free. We presume that with enough effort it could have been exploited to run arbitrary code.

 

[nukecad 7]

Firefox 85.0 Released 26 Jan 2021.

• 13 Security fixes.
• Flash completely removed. No setting available to re-enable Flash support.
• Changes to how Supercookies are handled.
• Chages to how Bookmarks/Favourites and Saved Passwords are handled.

https://www.mozilla.org/en-US/firefox/85.0/releasenotes/

 

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ff v78.7.0 esr

26. jan 2021

Fixed

• Various stability, functionality, and security fixes

Quote

Security Vulnerabilities fixed in Firefox ESR 78.7

Announced January 26, 2021

Impact high

Products Firefox ESR

Fixed in

• Firefox ESR 78.7

#CVE-2021-23953: Cross-origin information leakage via redirected PDF requests

Reporter Rob Wu

Impact high

Description

If a user clicked into a specifically crafted PDF, the PDF reader could be confused into leaking cross-origin information, when said information is served as chunked data.

References

• Bug 1683940

#CVE-2021-23954: Type confusion when using logical assignment operators in JavaScript switch statements

Reporter Gary Kwong

Impact high

Description

Using the new logical assignment operators in a JavaScript switch statement could have caused a type confusion, leading to a memory corruption and a potentially exploitable crash.

References

• Bug 1684020

#CVE-2020-26976: HTTPS pages could have been intercepted by a registered service worker when they should not have been

Reporter Andrew Sutherland

Impact moderate

Description

When a HTTPS page was embedded in a HTTP page, and there was a service worker registered for the former, the service worker could have intercepted the request for the secure page despite the iframe not being a secure context due to the (insecure) framing.

References

• Bug 1674343

#CVE-2021-23960: Use-after-poison for incorrectly redeclared JavaScript variables during GC

Reporter Irvan Kurniawan

Impact moderate

Description

Performing garbage collection on re-declared JavaScript variables resulted in a user-after-poison, and a potentially exploitable crash.

References

• Bug 1675755

#CVE-2021-23964: Memory safety bugs fixed in Firefox 85 and Firefox ESR 78.7

Reporter Mozilla developers and community

Impact high

Description

Mozilla developers Alexis Beingessner, Christian Holler, Andrew McCreight, Tyson Smith, Jon Coppeard, André Bargull, Jason Kratzer, Jesse Schwartzentruber, Steve Fink, Byron Campen reported memory safety bugs present in Firefox 84 and Firefox ESR 78.6. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.

References

• Memory safety bugs fixed in Firefox 85 and Firefox ESR 78.7

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ff v85.0.1

5. feb 2021

Fixed

• Security fix

• Prevent access to NTFS special paths that could lead to filesystem corruption.

• Fixed a crash when authenticating to websites using SPNEGO on macOS devices with Apple Silicon CPUs (bug 1685427).

• Avoid printing an extra blank page at the end of some documents (bug 1689789).

• Fixed a browser crash in case of unexpected Cache API state (bug 1684838).

• Fixed external URL scheme handlers when using the Firefox flatpak (bug 1688966)

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ff v78.7.1 esr

5. feb 2021

Fixed

• Security fix

• Prevent access to NTFS special paths that could lead to filesystem corruption.

Quote

Security Vulnerabilities fixed in Firefox 85.0.1 and Firefox ESR 78.7.1

Announced February 5, 2021

Impact critical

Products Firefox, Firefox ESR

Fixed in

• Firefox 85.0.1
• Firefox ESR 78.7.1

#MOZ-2021-0001: Buffer overflow in depth pitch calculations for compressed textures

Reporter Abraruddin Khan and Omair working with Trend Micro Zero Day Initiative

Impact critical

Description

In the Angle graphics library, depth pitch computations did not take into account the block size and simply multiplied the row pitch with the pixel height. This caused the load functions to use a very high depth pitch, reading past the end of the user-supplied buffer.
Note: This issue only affected Windows operating systems. Other operating systems are unaffected.
This issue has been assigned a temporary identifier, pending assignment of a CVE.

References

• Bug 1676636

 

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ff v85.0.2

9. feb 2021

Fixed

• Fixed a deadlock during startup (bug 1679933)

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ff v86.0

23. feb 2021

New

• Firefox now supports simultaneously watching multiple videos in Picture-in-Picture.

• Today, Firefox introduces Total Cookie Protection to Strict Mode. In Total Cookie Protection, every website gets its own “cookie jar,” preventing cookies from being used to track you from site to site.

• We've improved our Print functionality with a cleaner design and better integration with your computer's printer settings.
  

• For Firefox users in Canada, credit card management and auto-fill are now enabled.

Fixed

• Reader mode now works with local HTML pages.

• Using screen reader quick navigation to move to editable text controls no longer incorrectly reaches non-editable cells in some grids such as on messenger.com.

• The Orca screen reader's mouse review feature now works correctly after switching tabs in Firefox.

• Screen readers no longer report column headers incorrectly in tables containing cells spanning multiple columns.

• Links in Reader View now have more color contrast.

• Various security fixes.

Changed

• On Linux and Android, the protection to mitigate the stack clash attack has been activated.

• From Firefox 86 onward, DTLS 1.0 is no longer supported for establishing WebRTC's PeerConnections. All WebRTC services need to support DTLS 1.2 from now on as the minimum version.

• Consolidated all video decoding in the new RDD process which results in a more secure Firefox.

Enterprise

• Various bug fixes and new policies have been implemented in the latest version of Firefox. You can see more details in the Firefox for Enterprise 86 Release Notes.

Developer

Developer Information

• CSS image-set() function in CSS is now enabled, allowing for responsive images in CSS.

• Inactive CSS tool is now showing a warning when margin or padding is set on internal table elements.
  

• Developer Tools Toolbox is now showing a number of errors on the current page. This is a quick way to surface information to a developer that something is wrong with their page. Clicking on the red exclamation icon navigates the user to the Console panel.
  

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ff v78.8.0 esr

23. feb 2021

Fixed

• Various stability, functionality, and security fixes

Quote

Security Vulnerabilities fixed in Firefox ESR 78.8

Announced February 23, 2021

Impact high

Products Firefox ESR

Fixed in

• Firefox ESR 78.8

#CVE-2021-23969: Content Security Policy violation report could have contained the destination of a redirect

Reporter Masato Kinugawa

Impact high

Description

As specified in the W3C Content Security Policy draft, when creating a violation report, "User agents need to ensure that the source file is the URL requested by the page, pre-redirects. If that’s not possible, user agents need to strip the URL down to an origin to avoid unintentional leakage." Under certain types of redirects, Firefox incorrectly set the source file to be the destination of the redirects. This was fixed to be the redirect destination's origin.

References

• Bug 1542194

#CVE-2021-23968: Content Security Policy violation report could have contained the destination of a redirect

Reporter Ademar Nowasky Junior

Impact high

Description

If Content Security Policy blocked frame navigation, the full destination of a redirect served in the frame was reported in the violation report; as opposed to the original frame URI. This could be used to leak sensitive information contained in such URIs.

References

• Bug 1687342

#CVE-2021-23973: MediaError message property could have leaked information about cross-origin resources

Reporter Andreas Pehrson

Impact low

Description

When trying to load a cross-origin resource in an audio/video context a decoding error may have resulted, and the content of that error may have revealed information about the resource.

References

• Bug 1690976

#CVE-2021-23978: Memory safety bugs fixed in Firefox 86 and Firefox ESR 78.8

Reporter Mozilla developers

Impact high

Description

Mozilla developers Alexis Beingessner, Tyson Smith, Nika Layzell, and Mats Palmgren reported memory safety bugs present in Firefox 85 and Firefox ESR 78.7. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.

References

• Memory safety bugs fixed in Firefox 86 and Firefox ESR 78.8