Mozilla has released Firefox 151.0.2, a focused bug-fix update that targets Split View stability, a Windows crash tied to Chinese input methods, a macOS certificate loading failure, and several website rendering problems. The update carries no new features and follows Firefox 151.0.1, which addressed crashes on Intel Raptor Lake processors.
If you use Split View, type in Simplified Chinese on Windows, or noticed Firefox repeatedly downloading pages it should have cached, this update resolves all three issues directly.
What Is New in Firefox 151.0.2
Firefox 151.0.2 delivers ten bug fixes across Split View, input method compatibility, caching, macOS security hardware, and website rendering. Here is the full changelog from Mozilla.
Split View Fixes
Mozilla fixed two separate Split View bugs in this release.
The first bug caused Split View to close unexpectedly when a user added another tab to an existing Split View session. Instead of keeping the layout intact, Firefox dropped it entirely.
The second bug triggered when users selected the Switch to Tab option from the address bar while in Split View. Firefox closed Split View instead of switching to the selected tab.
Both fixes improve multitasking stability for anyone relying on Split View as a core part of their browsing workflow. If you have not tried Split View yet, the Firefox 150 update introduced the feature alongside the PDF Editor and privacy improvements.
Windows Crash With Sogou Input Method Fixed
Firefox 151.0.2 fixes a crash on Windows that occurred when users typed Simplified Chinese using the Sogou input method editor. The crash happened during active text input and affected systems running the Sogou IME.
Mozilla patched the underlying compatibility issue in this release. If you type in Simplified Chinese on Windows and Firefox was crashing during input, updating to 151.0.2 resolves it.
macOS Smart Card and Security Key Fix
On macOS, Mozilla fixed a bug where smart cards and hardware security keys sometimes failed to load certificates automatically. The failure affected users who rely on certificate-based authentication for enterprise access or physical security key login.
After this fix, smart cards and security keys load certificates correctly without requiring manual intervention.
Firefox Cache Bug Causing Repeated Downloads
Mozilla addressed a caching bug where Firefox stopped storing new content once the disk cache reached its limit. When the cache filled up, Firefox downloaded pages and resources from the network on every visit instead of loading them locally.
This fix restores normal caching behavior and reduces unnecessary bandwidth usage. Pages that Firefox previously cached correctly will load from local storage again after the disk cache fills.
Website and Web App Compatibility Fixes
Firefox 151.0.2 also resolves several rendering and compatibility issues affecting specific websites and web applications.
- WebKit-specific style rules: Some sites rendered incorrectly or failed to load when JavaScript inserted WebKit-specific CSS rules dynamically. Firefox now handles those rules without breaking the layout.
- Text selection in styled input fields: Clicking and selecting text inside certain input fields and text areas failed when the page applied specific CSS styling to those elements. The fix restores normal selection behavior.
- Number input field overlap: The up and down increment buttons on number input fields could overlap and hide the field value when a site sized the input to fit its contents. Firefox now renders the buttons correctly.
- String sorting with numbers: Some web apps sorted strings containing numbers in the wrong order. Mozilla corrected the sort logic so those results display accurately.
- Dropdown menus inside iframes: Dropdown menus for
<select>elements created inside an iframe and then moved into the parent page failed to open. This fix restores proper dropdown behavior for those elements.
How to Update to Firefox 151.0.2
Firefox delivers this update automatically through its built-in update system. To trigger the update manually:
- Open Firefox.
- Click the hamburger menu (three lines) in the top-right corner.
- Go to Help > About Firefox.
- Firefox checks for updates and installs 151.0.2 automatically.
- Click Restart to Update when prompted.
You can also download Firefox 151.0.2 directly:
Is Firefox 151.0.2 Worth Installing?
Yes. The Split View fixes alone make this update worth installing immediately if you use that feature. The Sogou IME crash fix is critical for Windows users who type in Simplified Chinese. The caching fix benefits everyone by stopping unnecessary re-downloads on repeat visits.
Firefox 151.0.2 carries no risk since it introduces no new features, only targeted fixes for confirmed bugs.
If you also want to get more out of your updated browser, check out how to use Firefox’s built-in VPN and pick your server location added in Firefox 151.
