Firefox 145.0

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This version introduces a new phase of privacy protections, building on our research on reducing browser fingerprinting . These new defenses cut the percentage of users seen as unique almost in half, ensuring a safer and more private browsing experience in Private Browsing or when using Enhanced Tracking Protection set to Strict .

Need a reminder of what tabs are in a group? Hover over the tab group name to get a preview of the tabs inside without opening it. Tab Hover Preview Video demonstration

You can now access and manage your saved passwords right from the sidebar—no need to open a new tab or window. Stay on the page you’re on and get to your logins faster.

Copy Link to Highlight allows users to share arbitrary sections of a page with others by copying a link through the context menu with a given selection

The Translations feature has an improved experience when translating between languages with different script directions.

New brand-inspired wallpapers are available for New Tab on desktop, with versions for both light and dark mode.

With the new Open links from apps next to your active tab setting, you can have links from other applications open next to your active tab instead of at the end of the tab strip.

Enhanced Bounce Tracking Protection’s stateless mode is now enabled by default in ETP Strict , blocking more advanced tracking techniques based on redirection

For most Windows users, the existing desktop shortcut for launching Firefox has been replaced with the desktop launcher, a small program that will launch Firefox if it is installed, but if it is not installed will prompt the user to install Firefox. This will provide an easy installation point for Firefox users who acquire a new Windows device, where Firefox will not be installed by default, but the desktop launcher program may have synced via OneDrive or other cloud storage product. Learn more .

Firefox no longer supports 32-bit Linux systems . We recommend installing the 64-bit version for continued updates and support.

Horizontal tabs are now slightly more rounded to match the look of vertical tabs. Buttons and text inputs, including the address bar, have also been updated for consistency.

When no extensions are installed, clicking the Extensions button now shows a message highlighting how extensions can enhance your browsing, with links to the Firefox Add-ons store.

Local translation models are now compressed with Zstandard , reducing download sizes and on-device storage consumption. As always, all Firefox translations happen securely and privately on your local device, unlike other browsers that translate using cloud services.

We updated default automation preferences to better support Agentic browsing, reducing the steps agents need to complete a task and chances for the agent to get stuck.

On Windows, clicking tabs may not work at the very top of the screen when Firefox is maximized on a second monitor. We’re working to fix this in a future release. (Fixed in 147.0)

Various security fixes .

When Bounce Tracking Protection (BTP) is enabled, it now runs in "stateless" mode by default. In "stateless" mode, the browser no longer only flags sites that are part of a "bounce" that set state information (such as a cookie); it flags all sites that are part of a "bounce". See Bounce tracking mitigations for more information on how BTP works. ( Firefox bug 1990831 ).

You can find information about policy updates and enterprise specific bug fixes in the Firefox for Enterprise 145 Release Notes .

Developer Information

Microsoft UI Automation phased release rollout at 100%. Microsoft UI Automation is the new accessibility framework for Microsoft Windows. This will provide better assistive technology (AT) support and performance on Windows for current and future assistive technologies.

With the release of Firefox 145, we are pleased to welcome the developers who contributed their first code change to Firefox in this release, 5 of whom were brand new volunteers! Please join us in thanking each of these diligent and enthusiastic individuals, and take a look at their contributions: Alex Hill: 627771

Cookies created with cookies.set() are now validated, and invalid cookies are rejected. This change was implemented in Nightly only from Firefox 142. ( Firefox bug 1976509 )

CSS anchor positioning (Nightly): layout.css.anchor-positioning.enabled Nightly builds now support CSS anchor positioning by default, which allows you to tether elements together. The anchor-positioned elements can then have their size and position set relative to the size and location of the anchor elements to which they are bound. (General: Firefox bug 1988224 , position-area : Firefox bug 1924086 , custom @position-try fallbacks: Firefox bug 1962598 ).

CSS module scripts: (Nightly) and layout.css.module-scripts.enabled . CSS module scripts are now supported, allowing a stylesheet to be loaded into a script as a CSSStyleSheet instance using the import keyword and the type import attribute set to type="css" . ( Firefox bug 1720570 ).

text-decoration-trim : layout.css.text-decoration-trim.enabled The CSS text-decoration-trim property is supported but currently disabled by default. It allows you to specify text-decoration start and end offsets to shorten, lengthen, or shift the position of text decorations with respect to the text ( Firefox bug 1979915 ).

Trusted Types API for scripts (Nightly/Early Beta): dom.security.trusted_types.enabled The Trusted Types API is now enabled in early beta releases. ( Firefox bug 1976656 ). The changes include:

Addition of the TrustedTypePolicyFactory , TrustedTypePolicy , TrustedHTML , TrustedScript , TrustedScriptURL interfaces, and the trustedTypes property on Window and WorkerGlobalScope .

Updates to injection sink interfaces APIs, such as Element.innerHTML and document.write() , to allow the TrustedHTML , TrustedScript , TrustedScriptURL to be passed as well as strings.

Support for the require-trusted-types-for and trusted-types directives, and the 'trusted-types-eval' keyword, of the Content-Security-Policy HTTP header. These can be used to enforce trusted types instead of strings, name the specific policies that are allowed, and to enable eval() and similar functions to be used when Trusted Types are supported and enforced.

Storage Access headers (Nightly): dom.storage_access.headers.enabled . The Sec-Fetch-Storage-Access and Activate-Storage-Access HTTP headers are now supported, enabling a more efficient Storage Access API workflow. ( Firefox bug 1991688 ).

Support has been added for the Atomics.waitAsync proposal, which is a non-blocking, asynchronous version of Atomics.wait . This allow synchronization of threads based upon the value in a shared memory location, for more details please consult our MDN documentation .

Firefox now supports the new Integrity-Policy header for enforcing sub-resource integrity for scripts. Further implementation of this header is underway.

Added Matroska support for the most commonly used codecs: AVC, HEVC, VP8, VP9, AV1, AAC, Opus, and Vorbis.

The text-autospace property is now supported, allowing automatic spacing adjustments between characters from different scripts.

The WebGPU DOM API ( spec ; MDN ) is now available on macOS 26 (Tahoe) on Apple Silicon. For details, see the Mozilla Graphics Team Blog .

The text-autospace property is now supported, allowing automatic spacing adjustments between characters from different scripts ( Firefox bug 1981086 , Firefox bug 1869577 ).

The math generic font family is now supported as a value of the font-family property, allowing mathematical expressions to use appropriate fonts. ( Firefox bug 1788937 ).

Separators can appear in <select> menus since <hr> in <select> was implemented. These are now also supported in Firefox for Android. ( Firefox bug 1867045 , Firefox bug 1830909 ).

Firefox now supports the Atomics.waitAsync() static method, which allows synchronization of threads based upon the value in a shared memory location. The method waits asynchronously for the value and returns an object representing the operation's result. It is non-blocking and usable on the main thread. ( Firefox bug 1884148 ).

The Integrity-Policy and Integrity-Policy-Report-Only HTTP headers are now supported for script resources. These allow websites to enforce subresource integrity guarantees for scripts . Note that the endpoints key is not yet supported (violations are logged to console). ( Firefox bug 1984973 ).

The source property of the ToggleEvent interface is now supported. If a popover is triggered to open or close by an HTML element such as a <button> , the event's source property will contain the element that triggered the popover. ( Firefox bug 1968987 ).

A CSSStyleProperties instance is now returned for the style property on HTMLElement , MathMLElement , SVGElement , and CSSStyleRule , and the Window.getComputedStyle() method. Previously a CSSStyleDeclaration instance was returned. ( Firefox bug 1989925 )

RTCEncodedVideoFrame and RTCEncodedAudioFrame are now serializable objects , and RTCEncodedAudioFrame() and RTCEncodedVideoFrame() copy constructors are supported. These changes allow frames to be cloned, and to be shared between workers and the main thread. ( Firefox bug 1868223 and Firefox bug 1975032 ).

The Matroska container ( .mkv ) is now supported for the most commonly-used codecs: AVC, HEVC, VP8, VP9, AV1, AAC, Opus, and Vorbis. ( Firefox bug 1991752 ).

Implemented the emulation.setUserAgentOverride command, which allows to override the user-agent string used by the browser either for a set of contexts, user contexts or globally. ( Firefox bug 1987935 ).

Implemented the browsingContext.downloadEnd event, which is emitted when a download finishes (whether it is successful or canceled) ( Firefox bug 1970293 ).

Updated the destination property of the network.beforeRequestSent event to document for top-level navigations. ( Firefox bug 1985552 ).

Updated the browsingContext download events to reuse the same navigation id as the previous browsingContext.navigationStarted event. ( Firefox bug 1986938 ).

Fixed a bug for network data collection, where non-ASCII characters in response bodies were not properly encoded. ( Firefox bug 1986022 ).

Fixed a bug with the network.getData command, which would fail requests with an empty response body. ( Firefox bug 1986025 ).

Fixed a bug where some network events could be flagged as blocked even if they were not. ( Firefox bug 1989919 ).