Critical Firefox update (40.0.3) available now for Fedora

Mozilla just released a new update to Firefox — the default web browser in Fedora — that resolves a pair of high priority security issues. These updates are now available in the Fedora 21, Fedora 22 and prerelease Fedora 23 repositories. It is highly recommended that all users of Firefox update to version 40.0.3 using the Software application in Fedora Workstation, or using the command

sudo dnf update firefox

from the terminal. Note also that these updates are still propagating to all the mirrors, so you might not see these updates yet, but they will appear soon.

The updated version of Firefox resolves theĀ Add-on notification bypass through data URLs and Use-after-free when resizing canvas element during restyling issues, in addition to a handful of other bugfixes.

Fedora Project community


  1. yamaplos

    sudo dnf update firefox merely gives me a “dependencies resolved”.

    Xfce Fedora spin.

  2. try “sudo dnf clean all && sudo dnf update”

    • @marcin: Actually, it’s probably better to do

      dnf clean metadata

      instead of

      dnf clean all

      . That will avoid removing material the user may want to retain, and should accomplish the same goal.

  3. yamaplos

    @maecinm @Paulm

    thank you

    I tried the “metadata” one, got a pile of “Curl error”, as quoted below, ending with a “nothing to do”, still have good old Firefox 38.0.5

    Ran it again, even adding “firefox”
    sudo dnf clean metadata && sudo dnf update firefox

    this time no Curl errors, but same “nothing to do”

    I made a copy of my firefox data, I guess I could try the “clean all”… But looks as if somegow this thing is not finding anything fresh in the repos,

    attempt 1
    Cleaning repos: fedora rpmfusion-free-updates adobe-linux-x86_64
    : rpmfusion-nonfree-updates rpmfusion-free updates
    : rpmfusion-nonfree
    34 metadata files removed
    15 dbcache files removed
    The enabled repos were expired
    Fedora 20 – x86_64 7.4 MB/s | 36 MB 00:04
    Failed to synchronize cache for repo ‘rpmfusion-free-updates’ from ‘’: Cannot prepare internal mirrorlist: Curl error: Couldn’t connect to server for, disabling.


    Dependencies resolved.
    Nothing to do.

    attempt 2
    34 metadata files removed
    15 dbcache files removed
    The enabled repos were expired
    Fedora 20 – x86_64 7.4 MB/s | 36 MB 00:04
    RPM Fusion for Fedora 20 – Free – Updates 536 kB/s | 488 kB 00:00
    Adobe Systems Incorporated 22 kB/s | 1.8 kB 00:00
    RPM Fusion for Fedora 20 – Nonfree – Updates 378 kB/s | 178 kB 00:00
    RPM Fusion for Fedora 20 – Free 621 kB/s | 487 kB 00:00
    Fedora 20 – x86_64 – Updates 6.2 MB/s | 29 MB 00:04
    RPM Fusion for Fedora 20 – Nonfree 212 kB/s | 289 kB 00:01
    Dependencies resolved.
    Nothing to do.

  4. Patricia

    Hello, I do not know anything about programming, but my husband uses fedora on our pc. All family members have an account and we use it. When I logged in today and went to firefox, it said there was an update and to type a command on the terminal to get it. I did so, but it told me that I am not a sodoer? and it will be reported. What does that mean?

    • Luya Tshimbalanga

      Hello Patricia,
      sudoer is roughly an equivalent of administrator. It mean you account is set to standard mode found on Settings -> Users.
      Basically doing “sudo dnf upgrade firefox” will not run on your account due to the lack of administrator authorization. Ask your husband to do it or ask him to assign you as administrator.

  5. John Quinn

    My browser is Foxfire 40.0.3 silverlight needs a fix. It never works. It keeps crashing. There are no Foxfire add-ons to help me with this issue. Please help. Thank you!

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