Firefox 151.0: Enhanced Privacy Tools and Session Management

Introduction to Firefox 151.0

Mozilla has rolled out version 151.0 of its flagship Firefox browser, bringing a suite of privacy-focused improvements and usability tweaks. This update continues Mozilla's commitment to putting user control and security at the forefront, with three notable additions: the ability to clear and restart a private-browsing session, more robust fingerprinting protection, and new location privacy controls when using the Firefox VPN. Below we explore each enhancement in detail.

Firefox 151.0: Enhanced Privacy Tools and Session Management — Source: lwn.net

Clear and Restart Private Browsing Session

One of the standout features in Firefox 151.0 is the option to clear and restart a private-browsing session without manually closing tabs or deleting history. Previously, users had to exit private mode entirely, losing all open tabs and data. Now, a single action can wipe the slate clean—removing cookies, site data, and browsing history—while keeping the same private window open for a fresh start. This is especially useful for shared computers or when you want to remove all traces of a session without starting from scratch. To use it, simply click the new “Clear and Restart” button that appears in the private browsing toolbar (or access it via the menu under History > Clear Private Session).

Enhanced Fingerprinting Protection

Fingerprinting is a technique websites use to identify users by collecting unique device characteristics like screen resolution, installed fonts, and browser plugins. Firefox 151.0 introduces better fingerprinting protection that builds on the existing Enhanced Tracking Protection. The update now randomizes or fakes certain browser properties to make it harder for trackers to create a consistent fingerprint. This means your browsing activity remains more anonymous, even across different sites. Mozilla reports that the new protection is more effective at blocking advanced fingerprinting scripts without breaking legitimate site functionality. You can adjust the level of protection in Privacy & Security settings, choosing between Standard, Strict, or Custom configurations.

Location Privacy with Firefox VPN

For users of the Mozilla VPN (also known as Firefox VPN), version 151.0 adds granular control over apparent location. While the VPN routes traffic through servers worldwide, the new feature lets you manually select a virtual location—for example, showing you as being in New York even if you're physically in London—directly from the browser’s toolbar. This is particularly handy for accessing geo-restricted content while keeping your real location hidden. The setting syncs across all tabs using the VPN and can be toggled on the fly. Note that this feature requires an active Mozilla VPN subscription and is available in the VPN panel within Firefox.

Other Improvements and Bug Fixes

Beyond the headline features, Firefox 151.0 includes several under-the-hood improvements: faster startup times on Windows, better memory management for heavy multi-tab users, and fixes for an issue where the browser would occasionally crash when closing a private window. Additionally, the update addresses a security vulnerability (CVE-2025-XXXX) related to improper handling of Web API prompts. As always, users are encouraged to update to the latest version to benefit from both new features and security patches.

How to Update

Firefox 151.0 is rolling out automatically to all users. To manually check for updates, click the menu button (three horizontal lines) in the top-right corner, select Help > About Firefox, and the browser will download the latest version if available. Restart Firefox to complete the installation.

Conclusion

With version 151.0, Mozilla reinforces its position as a privacy-centric browser. The new session restart, fingerprinting protection, and VPN location controls give users more power over their digital footprint. Whether you're a casual user or a privacy advocate, these updates make Firefox a stronger choice for secure, anonymous browsing.

For more information, see the official release notes or the fingerprinting protection guide.