Firefox 151 packs big privacy upgrades into a small update
Firefox 151 packs big privacy upgrades into a small update
Publish Date: 2026-05-20 08:07:00
Source Domain: www.malwarebytes.com
Mozilla has published release notes for Firefox browser version 151.0, and this update includes several genuinely meaningful privacy and security improvements.
Three changes stand out in particular:
- Stronger anti‑fingerprinting
- Broader protection for local network access
- More control over private sessions and permissions
Note that Mozilla says several Firefox 151 features are “part of a progressive roll out,” meaning they will appear for some users first and be expanded over time. So, you may not see all of them immediately.
Privacy
One of the more visible additions is a new “end private session” control in Private Browsing Mode. Instead of closing every private window to clear your traces, you now get a dedicated fire‑icon button next to the address bar that wipes the current private session’s data and immediately starts a fresh one.
End private session button
Under the hood, this clears the usual private browsing artifacts for that session, including history, cookies, cached files, and other site data that would normally disappear only when the last private window closes.
For people who routinely mix normal and private windows, this is safer and less error‑prone than hunting down every private tab before you walk away from the machine.
Firefox 151 also tightens its defenses against browser fingerprinting in the default “Standard” Enhanced Tracking Protection (ETP) mode. Mozilla says Firefox now limits the amount of device and browser information exposed to websites in a way that reduces the number of uniquely identifiable users by about 14% overall, and by roughly 49% on macOS.
This makes it harder for trackers to pick you out of the crowd, especially on platforms with fewer users to begin with (like certain macOS configurations). This reduces the privacy risk surface by default, which makes it harder for phishing and landing pages that redirect visitors to “categorize” you.
Another…
