Mozilla is rolling out Firefox 145 with substantial upgrades to its anti-fingerprinting technology, cutting the percentage of users that can be uniquely identified by fingerprinters by nearly 50%.
The improvements represent the second phase of a broader privacy initiative targeting stealth tracking techniques that operate outside of known tracker lists.
The update, officially launching on November 11, 2025, was detailed by Tom Ritter, a senior security engineer at Mozilla, who emphasized Firefox's ongoing efforts to combat browser fingerprinting. This form of tracking creates a unique profile of users by collecting subtle configuration and behavioral details, such as hardware specifications, installed fonts, time zones, and even performance quirks in how devices process graphics or mathematical operations. Unlike cookies, fingerprinting persists across sessions and often bypasses private browsing protections, making it a favored tool of surveillance advertisers and other persistent trackers.
Firefox's fingerprinting countermeasures build on previous protections introduced since 2021, which initially addressed the most commonly exploited vectors. In this latest release, Mozilla is closing more advanced fingerprinting gaps by limiting access to system-level information. For example, Firefox now shields data points like processor core count, touchscreen input capabilities, and taskbar dimensions, details frequently abused by tracking scripts to improve fingerprint uniqueness.
Mozilla, a nonprofit known for its strong privacy stance, has been developing Firefox as a privacy-respecting alternative to mainstream browsers. Enhanced Tracking Protection (ETP), introduced in 2020, automatically blocks known trackers and malicious scripts. Since then, Firefox has introduced Total Cookie Protection and steadily expanded its defenses against more subtle and unlisted tracking tactics. Firefox's current fingerprinting protections are now available in Private Browsing Mode and ETP Strict mode, with Mozilla planning to enable them by default after further validation.
Mozilla has opted for a layered approach rather than aggressive blocking, which could break legitimate web features such as calendar synchronization or video conferencing tools that rely on accurate time zones or device information. The browser now preemptively limits the exposure of high-risk data while still allowing necessary functionality, ensuring users are less trackable without degrading their experience.
In addition to its privacy upgrades, Firefox 145 introduces several user-facing features. These include a new PDF annotation system with support for adding, editing, and organizing comments, improvements to tab group previews, and a more polished UI with rounded tabs and elements.
Notably, Firefox 145 ends official support for 32-bit Linux systems on x86 architecture. Mozilla cited the declining use of 32-bit Linux and increased maintenance overhead as reasons for discontinuation, recommending users migrate to 64-bit systems for continued updates.
Firefox 145 will be made available as an update to existing users tomorrow, but those who can't wait can download it immediately from Mozilla's FTP servers.
For maximum privacy on Firefox, check out our guide here.
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