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Firefox 139.0.4 fixes browser freezes, wallpaper bugs on Windows, and more

Firefox 13904

Mozilla is rolling out a new update for Firefox 139. Version 139.0.4 arrived today with four fixes and security patches. With today's release, Mozilla fixes freezes that occur when switching between apps or opening certain parts of the browser, issues with drop-down menus and triple-clicking text, and a bug with incorrect file names when setting a picture as the desktop background on Windows (the image would save as a BMP file with a blank name instead of Desktop Background.bmp)

Here is the changelog:

  • Fixed Firefox freezing when switching between apps or opening certain panels within the browser. (Bug 1969253 & Bug 1969346)
  • Fixed difficult selection of drop-down menu options in the Firefox preferences page when selected via the in-page search. (Bug 1968949)
  • Fixed various selection issues when triple-clicking text in some situations. (Bug 1969100 & Bug 1969432)
  • Fixed an incorrect filename being used when setting an image as the desktop wallpaper on Windows. (Bug 1969793)
  • Various security fixes.

Security updates in Firefox 139.0.4 include two patches for vulnerabilities of high impact:

  • CVE-2025-49709: Memory Corruption in canvas surfaces. Certain canvas operations could have led to memory corruption.
  • CVE-2025-49710: Integer overflow in OrderedHashTable. An integer overflow was present in OrderedHashTable used by the JavaScript engine.

As usual, you can update Firefox by heading to Menu > Help > About Firefox. Alternatively, grab the browser from the official website, Microsoft Store (if you are on Windows 10 and 11), or Neowin's Software page. For reference, release notes for version 139 and its subsequent bug-fixing update, 139.0.1, are available here and here.

In other Firefox news, Mozilla recently announced the end of Pocket, Fakespot, and some other services. The company says its goal is to consolidate efforts and focus on Firefox development, its primary product.

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