Firefox 151 Enhances Privacy and Security with Major Updates and Over 30 Patches
What’s New in Firefox 151
Mozilla’s latest release for Windows, macOS, Linux, and Android introduces significant privacy improvements, updates to the built-in PDF viewer and editor, and enhancements to the VPN service. Alongside these features, over 30 security vulnerabilities have been addressed. Users on Extended Support Release (ESR) versions also receive these fixes.
VPN Enhancements
The complimentary VPN service, first launched in Firefox 149, now allows users to choose from multiple virtual locations. Available in the United States, Canada, the United Kingdom, France, and Germany, the VPN offers these same countries as connection options. To use the service, you’ll need a free Mozilla account, and you’ll receive 50 GB of VPN traffic each month. The location selection feature is rolling out gradually.
Private Browsing Upgrades
In private windows, users can now clear an entire session with a single button click—no need to close the browser. This action starts a fresh private session with no browsing history. Additionally, tracking protection has been refined. Mozilla claims this reduces the number of users identifiable via standard fingerprinting techniques by 14 percent overall, with up to a 50 percent reduction on macOS alone.
New Tab Page and PDF Editor
The revamped “New Tab” page now includes more background images and is ready for upcoming features that Mozilla plans to introduce before Firefox 152 arrives on June 16. The built-in PDF viewer and editor has gained the ability to merge multiple PDF files into a single document. Furthermore, the internal page for translating text (about:translations) is now accessible via the menu under “More Tools.”
Linux Profile Backup
Linux users can now back up their Firefox profiles locally and restore them across different platforms, making it easier to migrate settings and data.
Security Flaws Fixed in Firefox 151
According to Mozilla’s Security Advisory 2026-46, over 30 vulnerabilities have been patched. Of these, 28 were discovered and reported by external security researchers.
Mozilla classifies four of those externally reported vulnerabilities as high risk, including a potential escape from the browser sandbox (CVE-2026-8945). Eleven vulnerabilities are rated medium risk, and the remaining are low risk. The final three entries in the advisory cover internally discovered issues stemming from programming errors in memory management.
Tip: Keeping your browser up to date is essential, but you should also consider reliable antivirus protection and a VPN for enhanced security. Check out our recommendations for the best antivirus software for Windows and top VPN services to stay ahead of potential threats.
Other Browser Updates
In addition to Firefox 151.0, Mozilla has released ESR versions 140.11.0 and 115.36.0. The latter is available only for Windows 7/8.1 and macOS versions 10.12 to 10.14. These ESR updates include fixes for the vulnerabilities that were already present in the corresponding codebase.