Firefox 151: Enhanced Privacy, VPN Location Choices, and 30+ Security Fixes

Mozilla's latest Firefox update, version 151, brings a host of privacy enhancements, a revamped VPN feature, improvements to the PDF editor, and critical security patches. This release is available for Windows, macOS, Linux, and Android, alongside updates for ESR versions. Below, we delve into the most notable changes in a Q&A format.

What privacy enhancements does Firefox 151 introduce?

Firefox 151 steps up user privacy in several ways. Private browsing sessions now feature a one-click erase button to wipe all history and start fresh without closing the window. Additionally, tracking protection has been tightened, with Mozilla claiming a 14% reduction in identifiable users through standard fingerprinting techniques overall, and up to 50% on macOS alone. These measures help shield your online activities from advertisers and trackers.

How has the built-in VPN feature improved?

The free VPN introduced in Firefox 149 now offers multiple virtual locations. Users in the US, Canada, UK, France, and Germany can select from these same countries as VPN endpoints, with a gradual rollout. A free Mozilla account grants 50 GB of monthly VPN traffic. This feature provides greater flexibility for bypassing geo-restrictions and encrypting your connection.

What new capability does the PDF viewer/editor have?

The built-in PDF tool now supports merging multiple PDF files into a single document. This addition simplifies document management without requiring third-party software. The feature is accessible from within the PDF viewer, making it easy to combine reports, forms, or presentations directly in your browser.

Which security vulnerabilities were fixed in Firefox 151?

Mozilla's Security Advisory 2026-46 lists over 30 fixed flaws, 28 from external researchers. Four are rated high risk, including a browser sandbox escape (CVE-2026-8945). Medium risk flaws total 11, with the rest low risk. Three internal bugs from memory management programming errors were also resolved. Regular updates are crucial to maintaining security.

What other updated versions were released alongside Firefox 151?

Alongside Firefox 151.0, Mozilla released ESR versions 140.11.0 and 115.36.0. The latter supports Windows 7/8.1 and macOS 10.12–10.14. These enterprise-oriented updates include fixes for vulnerabilities present in the corresponding codebase, ensuring legacy systems remain protected.

How is the New Tab page refreshed in Firefox 151?

The New Tab page receives a visual makeover with additional background images. It also prepares for upcoming features leading to Firefox 152 on June 16th. While the core functionality remains, these enhancements aim to make the start page more personalized and engaging for users.

What is the impact of improved tracking protection?

Firefox 151's enhanced anti-fingerprinting measures reduce the number of identifiable users by 14% overall, with macOS users seeing up to 50% reduction. This means advertisers can less reliably track you via device quirks and browser characteristics. Combined with the one-click session clearing in private mode, users gain stronger control over their digital footprint.