Pale Moon: Release notes
This is a major development and bugfix update.
- Redesigned the about box.
- Added "Check for updates" menu entries to the AppMenu and
classic menu (since the About box redesign no longer has application
update in it).
- Restored the
app.update.url.override pref for
- Added "Loop" control to html5 video.
- Fixed a crash with frames (e.g. when using Tile Tabs).
- Fixed an issue with textarea placeholders (spec compliance).
- Removed the Windows Maintenance Service one last time.
- Improved http basic auth DoS heuristics.
- Fixed an issue on big-endian machines (e.g. PPC64/linux).
- Removed e10s code from widgets.
- Preffed the various http "Accept" headers and aligned with
the Fetch spec (except for image requests).
URLSearchParams with the spec.
- Updated several site-specific UA overrides.
- Fixed "Yet Another special case of a flex frame being the
absolute containing block"™
- Fixed border drawing when the tab bar is hidden.
- Pref-controlled and disabled the use of unboxed plain
- Improved handling of interrupted connections through
proxies and pseudo-VPN extensions.
- Removed contextual identity.
- Updated the 7zip installer stub to a much more recent code
- Fixed an issue with applying percentages to 0 in layout
- Fixed an issue with calculating linear sums in JS JITed
- Added default value feature to
- Fixed an issue that would occasionally overwrite the new
tab custom URL.
- Updated the SQLite library to 3.27.2
- Killed the crashreporter toolkit files and exception
- Fixed an issue with a missing border on the tab bar when on
- Fixed a crash with badly-formatted SVG files.
- Showed the robots to the exit after squatting in the
browser for decades.
better and more logical parsing of JS code.
- Removed support code and leftovers for unsupported SunOS,
AIX, BEOS, HPUX and OS/2 operating systems.
- Fixed a scrollbar arrow issue on OS X.
- Removed all Firefox Accounts code.
- Made the CSS parser more robust and aligned
behavior with the CSS3 spec in case of bad input.
- Fixed an issue with blocklist updates not actually
dynamically applying due to a wrong URL.
- Updated the embedded emoji font to the TweMoji v11.4.0
- Fixed an issue with async/deferred scripts preventing page
loads from completing.
This is a security and bugfix update.
- Fixed hover state arrows on some controls.
- Fixed potential denial-of-service issues involving FTP
(loading of subresources and spamming errors).
- Disabled Microsoft Family Safety (Win 8.1) by default. This
prevents security issues as a result of a local MitM setup.
- Added several site-specific overrides (Firefox Send and
polyfill.io) to work around website UA-sniffing isues.
- Implemented the origin-clean
algorithm for controlling
access to image resources.
- Cleaned up the helper application service code.
- Ported applicable security fixes from Mozilla
CVE-2019-9792, CVE-2019-9796, CVE-2019-9801, CVE-2019-9793,
CVE-2019-9794, CVE-2019-9808 and ZDI-CAN-8368).
- Implemented several defense-in-depth measures (for
- Fixed several memory safety hazards and crashes.
- Binaries are now code-signed again (including the setup
program for the installer).
This is a major development, stability and security release.
- Removed more telemetry code from the platform.
- Fixed implementation of the
API to avoid crashes, and enabled it by default.
- Switched to the new ffmpeg decode API to avoid dropping of
- Fixed a buffering issue in the WebP decoder that caused
intermittent browser crashes.
- Improved resource-efficiency for internal stopwatch timers.
- Improved handling of incorrectly-encoded CTTS in media
files, resolving some playback issues of videos.
- Improved the Cycle Collector and Garbage Collector.
- Improved fullscreen navigation bar handling in the
situation it has focus when switching to full screen.
instanceof with the final ES6 spec.
- Improved Windows DIB (bitmap) clipboard data handling.
- Exposed TLS 1.3 cipher suite prefs in about:config in case
people want to disable them individually.
- Allowed empty string on the
setter to clear URL query parameters from JS.
- Added a potential fix for external links not opening in the
current window/tab (untested).
- Enabled C++11 thread-safe statics in the entire application.
- Updated several preferences for integration with the new
DiD This means that
the fix is "Defense-in-Depth": It is a fix that does not apply to a
(potentially) actively exploitable vulnerability in Pale Moon, but
prevents future vulnerabilities caused by the same code, e.g. when
surrounding code changes, exposing the problem, or when new attack
vectors are discovered.
- Fixed a potential use-after-free in IndexedDB code. (DiD)
- Improved proxy handling to avoid localhost getting proxied.
- Ported upstream Skia fixes. (CVE-2018-18356, CVE-2018-18335)
- Fixed an additional Skia issue. (CVE-2019-5785)
- Fixed several potentially-exploitable memory safety hazards
and crashes. (DiD)
- Fixed a possible data race when performing compacting GC.
This is a minor bugfix and stability release.
If you are using a language pack, please make sure you have the
matching version for this browser version installed. Some strings were
added for Captive Portal detection (see below) and outdated language
packs will cause blank preference pages.
- Improved toolbar icon display for all DPIs on Windows.
- Disabled the IntersectionObserver API by default while we
work on resolving crashes caused by it.
isIntersecting to the
IntersectionObserver API per specification.
- Added an option to the preferences window to enable Captive
Portal detection (Advanced -> General). If your network connection
regularly encounters Captive Portals (e.g. using a laptop on the road
or other WiFi connections that require login or agreement to terms)
then enabling this detection may make your use of such networks more
For those worried about privacy: the detection service makes use of our
own infrastructure and does not contact third parties like Apple or
This is a major development and bugfix release.
- Added AV1 support for MP4/MSE videos. Please note that this
is a reference library implementation and the upstream decoding lib
currently has poor performance for higher resolutions (720p+). This is
disabled by default; use the about:config preference media.av1.enabled
to enable this codec.
- Changed the API used for video playback with FFmpeg 58+.
This should solve performance issues with VPx.
- Redesigned the main toolbar icons as SVG images to make
them HiDPI compliant.
- Fixed the sync notification (infobar) icon.
- Fixed a potential cycle collector resource leak.
- Added icons and controls to tabs to indicate if sound is
playing the tab and if so, allowing the user to mute it with a click.
This is a native implementation of the API in use in Basilisk and
performs the same function as the "expose noisy tabs" extension,
although the extension may still be preferred by some for e.g. skinning
capabilities. The feature may be disabled with browser.tabs.showAudioPlayingIcon.
- Removed support for VR hardware.
- Fixed out-of-bounds sizes for CSS calculation strings.
- Removed the DirectShow component since it is no longer
- Removed Firefox Accounts integration, phase 1:
- Changed the Sync client to the one from Tycho.
- Made Sync optional at build time.
- Stopped trying to cater to addons.mozilla.org since they no
longer offer anything useful to Pale Moon after the Great XUL Extension
- Added an option to process favicons for optimal sized
display and removing animations. Enable this with browser.chrome.favicons.process
- Fixed an incorrect preference reference in feed reader.
- Fixed an issue with lazy frame construction on
elements. This should solve
e.g. the use of mathjax in comments on stackoverflow.
- Media code improvements and cleanup (ongoing).
- Updated the DropBox useragent override to solve login
- Fixed potential crashes due to shutdown observers in VTT
and font lists. DiD
- Enabled some mistakingly-disabled optimizations in the JS
- Fixed several potential crashes in JS. DiD
- Fixed several potential crashes in WebCrypto. DiD
- Fixed a potential crash in JS Range Analysis. DiD
- Fixed a potential crash in the layout engine due to combo
- Fixed a potential shutdown crash in non-standard
environments related to 2D Canvas. DiD
- Fixed a potential overflow in the PNG writer. DiD
- Fixed a potential double-free in the MAR signing utility. DiD
- Fixed an issue where URLs could be extracted cross-origin (CVE-2018-18494).
- Updated NSPR to v4.20.
- Updated NSS to 3.41, providing (among other things) full
compatibility with the final version of TLS 1.3 on websites.
location.protocol to the latest spec.
- Updated Intersection Observers to the latest spec and
enabled them by default.
- Updated the SQLite lib to 3.26.0.
- Fixed errors about the login manager's recipeManager not
being available (yet).
- Switched status bar download arrow to SVG.
- Fixed a crash in IntersectionObservers.
- Fixed initialization of the Search service from browser
code to avoid synchronous init.
- Added logging of performance warnings to devtools consoles.
- Fixed favicons in taskbar tab preview listings.
- Blocked Comodo IS dll < version 6.3 to prevent startup
- Fixed issues in the HTML form submit observer module.
- Limited resolving depth of CSS variables to a sane maximum
(fixes cras.sh issue).
- Removed Mozilla's proprietary constructor on WebAudio's
aligning it with the standard specification.
- Exposed the previously hidden preference in about:config
for page thumbnail generation (some people prefer this for local
Element.ScrollIntoView with the DOM
specification. This improves, among other things, compatibility with
the React framework.
This is a minor update to address a few pertinent issues.
- Changed the about:feeds icon for external applications to a
generic icon, since that kind of access to executables is no longer
allowed for security reasons.
- Fixed issues with copying/pasting bookmarks in the Library
- Fixed a crash occurring when using HTTP pipelining over
some (broken) proxies.
- Fixed several issues with animated WebP display (animations
stopping, corrupted frames on lossy images, etc.)
- Fixed an issue with the display of truncated GIF images.
- Fixed an issue with deleting recent history not working
- Fixed incorrect duplicate compatibility mode preferences in
This is a bugfix release to address critical usability issues with the
This is a major development and bugfix release.
- Fixed a major performance issue with web workers.
- Fixed a rare crash on local networks with HTTP basic auth
and unsupported cipher suites.
- Fixed a performance/timer issue when leaving the browser
- Fixed an issue causing an empty dialog when launching
executable files from the browser.
- Fixed an issue preventing making entries to disallow sites
to store data for off-line use.
- Removed code to prevent extensions with binary components.
- Fixed an issue with common dialogs being sized incorrectly
for their content.
- Fixed an issue with event handling on the tab bar that
would cause frustrating behavior when trying to open/close tabs in
- Switched default behavior for scrolling when a context or
pop-up menu is open to allow scrolling, like in v27. This also affects
scrolling in very long menus, e.g. bookmarks.
- Added experimental Asynchronous Panning and Zooming (APZ)
for desktop use.
- Re-enabled the use and parsing of ICC v4 color profiles.
- Removed telemetry code from the caching subsystem.
- Improved full-screen detection for suppressing status
- Made all arguments passed to Init*Event() optional except
the first for parity with other browsers.
- Cleaned up some internal installer code.
- Fixed making caret width configurable when dealing with CJK
- Fixed drawing of table borders consistently when zooming a
- Exposed the "Save download location per site" pref in
- Improved media handling (ongoing).
- Added experimental support for AV1 in WebM videos (disabled
Note: this is for WebM only for now, so MP4 and MSE AV1 streams (e.g.
YouTube) will not (yet) play.
- Removed the (defunct and incomplete) in-browser translation
- Fixed an issue with CSS Grid layouts unnecessarily
shrinking element blocks.
- Fixed notification settings menu entry (opes
about:permissions with relevant data now).
- Fixed the launching of an undesirable background content
process for capturing page thumbnails.
- Fixed a focus issue in the bookmark properties dialog.
- Changed the setting for reporting CSS errors to the console
to false by default, to prevent unnecessary performance loss for
recording this data.
- Added control mechanisms for Opportunistic Encryption (both
for alternative services and upgrade-insecure-requests) in preferences,
and disabled this by default due to potential security and privacy
issues with this transitional technology.
- Updated the default reported Firefox version in Firefox
Compatibility Mode to prevent "too old Firefox" complaints on websites.
- Updated libnestegg, ffvpx, reader view components and
several other modules from upstream.
- Implemented security fixes for CVE-2018-12381,
CVE-2017-7797, a better fix for CVE-2018-12386 (DiD), CVE-2018-12401
(DiD), CVE-2018-12398, CVE-2018-12392, several Skia bugs, and several
crashes and memory safety hazards that do not have a CVE number.
This major update is focused on performance, security and some
regression and bug fixes.
- Updated NSS to 3.38, removed TLS 1.3 draft version check
since it's considered final.
- Reinstated RC4 as an optional encryption cypher for
non-standard environments (e.g. old routing/peripheral networked
hardware on LAN). RC4 and 3DES are marked weak and disabled, and will
never be used in the first handshake with a site, only as last-ditch
fallback when specifically enabled (meaning they won't show up on
ssllabs' test, for example).
- Removed Telemetry accumulation calls, automatic timers and
stopwatches. This removes a very noticeable performance sink for all
operations on all platforms.
- Fixed many occurrences of discouraged types of memory
access for primarily GCC 8 compatibility. This improves overall code
security as a defense-in-depth measure.
- Re-implemented the pref-controlled custom background color
for standalone images.
- Updated session history handling for internal pages.
about:logopage is no longer stored in history, and you can choose to
store the QuickDial page in history by setting the pref browser.newtabpage.add_to_session_history
to true. This is
disabled by default (meaning you can't use the "Back" button to go back
to the QuickDial page) as a defense-in-depth security measure.
- Added ui.menu.allow_content_scroll
to control whether content can be scrolled if a context menu is open.
- Fixed incorrect code removal in ipc.
- Removed support for TLS session caches in TLSServerSocket.
- Added support for local-ref as SVG xlink:href values.
- Changed the find bar to be a browser-global toolbar again
(like in Pale Moon 27) instead of per-tab. For people who prefer search
terms to be saved on a per-tab basis (like with the per-tab findbar
previously), this is possible by setting findbar.termPerTab to true. This resolves a number
of issues, including styling with lightweight themes not applying to
the find bar, and status pop-ups overlapping the find bar.
- Ported all relevant security fixes from Mozilla's Gecko/62
release, including CVE-2018-12377 and CVE-2018-12379.
- Restored part of the searchplugin API that was removed by
Mozilla, so extensions can provide and save edits to installed search
- Improved the speed of restoring browsing sessions upon
- Fixed the "Restore previous session" button sometimes being
missing from about:home, while a restorable session would be present.
- Fixed tab previews in the Windows taskbar (if enabled).
- Fixed the setting of the new tab page being "My Home Page"
so it'll pick up subsequent changes to the home page URL automatically.
- Removed the Firefox Accounts migrator from Sync.
- Fixed an issue with the enabled state of number controls if
- Stopped building ffvpx on 32-bit platforms (except windows)
to use the (faster) system-installed lib instead.
- Re-added a horizontal scroll action option for mouse wheel.
- Fixed handling of content language if the locale is changed.
- Fixed document navigation with the F6 key.
- Fixed toolbar styling in toolkit themes.
- Fixed viewing the source of a selection.
This is a bugfix point release to address serious performance
bottlenecks and general run-time issues (UI slowness, crashes, hangs)
with the browser. Once again this impacted 32-bit operating systems
more severely than 64-bit ones due to its more limited address space
that would get flooded with bogus data.
- Backed out a Mozilla upstream patch causing issues with IPC
and texture allocation for the compositor.
- Backed out a Mozilla upstream patch causing issues with
v220.127.116.11 (2018-08-28) - Windows only
This is a Windows-only update to address some stability/performance
issues that have popped up with the new milestone release on especially
The cause seems to be a compiler bug in Visual Studio 2015 with certain
optimizations. Although 64-bit does not seem to be directly affected,
we are still applying more cautious optimizations there too from this
point forward until we can figure out exactly what the cause is and
which (more aggressive) optimizations are safe to use.
We are excited to bring you Pale Moon 28.0. This is a new major
milestone in Pale Moon's release history.
We are now building on the Unified
Platform which has been forked off from Mozilla's mozilla-central
point before Rust and Quantum to continue focus on the XUL interface
language and traditional browser extensions. Many thousands of things
have changed since the v27 (AKA "Tycho") versions, which can't possibly
all be listed here. Instead, the most pertinent improvements in this
release are highlighted here:
What might be more important for people worrying about upgrading to
this milestone is what hasn't changed.
major upgrade and now supports all landmark features from the
ECMAScript standards as carried by mainstream browsers. This should put
frameworks not being browser-agnostic in that respect, or the browser
not supporting what websites expect.
- Goanna update: The layout and rendering engine (Goanna) has
been updated to its 4th generation (version 4.*) which brings with it
improved compatibility with "trendy" CSS styling techniques that build
on a few very specific features (e.g. CSS Grid). Goanna continues to
build on tried-and-tested software fallbacks in case hardware
acceleration can't be used, and Linux remote desktop users can continue
to leverage xrender for speedy remote screen updates in Pale Moon.
- DOM enhancements: Enhancements in the Document Object Model
provides websites with updated APIs to perform their tasks. (e.g.
Fetch, WebAnimations, WebCrypto, HTML Input Element Extensions, etc.)
- Media enhancements: Our media back-end update is, for all
intents and purposes, complete. MSE media streaming (for MP4) should be
compatible with all major players on the market now. MSE for WebM is
still disabled by default due to some compatibility issues that need to
be examined, but you may enable this in preferences to e.g. allow 4k
video playback on some sites that only offer UHD in WebM format. We now
also support playback of FLAC-encoded audio.
- New: WebGL2 support! Pale Moon now supports the WebGL2
standard for enhanced graphical experiences in 2D and 3D.
- Devtools have been given a refresh. Just in case you
thought they weren't extensive enough yet, some new categories have
added to inspect and manipulate all aspects of web content.
- Updates to the login manager: Login credentials can now be
stored specifically with or without a user name, and selected
individually. This is a behavior change from previous, and clicking a
password field can now pop-up a selection list of user names for which
passwords are stored (if multiple credentials are saved). Clicking the
appropriate login name (or date-stamped version if no name is present)
will fill in the accompanying password.
- We no longer support Windows Vista.
Our primary goal has been to lift Pale Moon up to the new platform and
as such most changes are "under the hood" and won't be seen in casual
use (aside from more things "just working"). We aim to keep your user
experience consistent and logical; but
some things will have changed, of course. Browser extensions may need
updating or may need a different version, for example.
- We continue to support NPAPI plugins.
- We continue to support complete themes as well as
- We continue to offer a fully customizable interface like
before. Australis (like seen in Basilisk) is not used.
- We continue to support XUL overlay, bootstrapped and
(deprecated) Jetpack extensions (collectively called "legacy
extensions" by Mozilla).
- We do not include
any DRM in the browser (people needing this can use e.g. the
Silverlight plugin to play protected content), even though the platform
we build on supports it.
Of course with such a big change of platform, there are some things
that have regressed (worked before but no longer work), and we will
work on fixing these regressions over time (hopefully with your help).
Reality check: Even though we have extensively tested the browser in
daily use for a few months (also thanks to the brave souls on our
unstable channel) we don't expect that the browser will be flawless or
bug-free. If you find bugs, regressions or issues with the new release,
discuss them on the forum. Let's work together as a community of users
to make this the best browser yet!
Big thank-yous and kudos go out
to everyone who has, in one way or another, contributed to this
milestone release and helped make it possible. This one belongs to all
Release notes for previous versions (unsupported)
You can find the release notes for previous releases of Pale Moon on
the Archived Versions Release