Red Hat 3.7 is ancient as it was released over twelve years ago on March March 17, 2006. RHEL 3 in general reached EOL on Oct 31, 2010 so you may have some more recent packages that may allow you to use Firefox versions from some years ago.

Firefox 1.5.0.1 was the then current Release when RHEL 3.7 was Released.

It is not the kernel version that Firefox Releases lines up with but some needed minimum package versions dependencies.

For example Firefox 46.0 and later versions from Mozilla requires GTK 3.4 (three.four which came out like seven years ago) and newer to run. Before that GTK 2.18 was the minimum for a long time.

The only supported versions with updates currently is Firefox 60.0 Release, 60.0 ESR and the old 52.0 ESR branch which will have last major 52.9.0 ESR update on June 26.

Any other versions are vulnerable.

But if you realty want to use a ancient vulnerable version you can play with the system-requirements url in changing the version for old versions until you find minimum requirements you may support for Firefox versions. Also check the Release notes for those versions as they can give changes in system requirements for Linux also. http://archive.mozilla.org/pub/firefox/releases/

https://www.mozilla.org/firefox/52.0/system-requirements/ https://www.mozilla.org/firefox/2.0/system-requirements/

https://www.mozilla.org/firefox/releases/

Oh ok so if I understand it well, Firefox only cares about the package of our linux version, not the kernel right ?

Also you're advicing me to try to Install one of the newest version of Firefox (52.0 ESR, 60.0 ESR or version before the 46.0) version on our old devices instead of the vunerables versions (1.5.0.1/2.0 ) ?

I would not be surprised if you could not run the Firefox 52.8.0esr from https://www.mozilla.org/firefox/organizations/all/ (click the Firefox 52 ESR on top as it defaults to 60 ESR). If you were to try the tar.bz2 where you extract it in a folder in some place like Home and then try running the firefox .sh in a terminal as it will give a output of errors including packages that is missing for example.

For example this is the packages requirements you will need to meet at minimum for to use Firefox 52 ESR.

https://www.mozilla.org/firefox/52.0/system-requirements/ Firefox will not run at all without the following libraries or packages:

• GTK+ 3.4 or higher
• GLib 2.22 or higher
• Pango 1.14 or higher
• X.Org 1.0 or higher (1.7 or higher is recommended)
• libstdc++ 4.6.1 or higher

If you were to use say Firefox 45.9.0 ESR as Firefox 46.0 started with GTK3. https://www.mozilla.org/firefox/45.0/system-requirements/ Firefox will not run at all without the following libraries or packages:

• GTK+ 2.18 or higher
• GLib 2.22 or higher
• Pango 1.14 or higher
• X.Org 1.0 or higher (1.7 or higher is recommended)
• libstdc++ 4.3 or higher

Why even still use such a old version of RHEL as there have been much newer versions of RHEL since and almost every Linux distros listed at http://distrowatch.org/ besides say Red Hat are free to download and use. There are still some that still supports 32-bit CPU's like Xubuntu and Lubuntu to name a couple that may be light enough to use.

Also If you have older hardware that uses a CPU that does not support say SSE2 then Firefox on Linux dropped support of those old CPU's as of Firefox 53.0 and later Releases. The old Intel P4 CPU's supports SSE2 however many AMD CPU's did not around that same time.

Also note Firefox 52 and later Releases requires PulseAudio to play sound and no longer plays sound directly with ALSA. https://www.mozilla.org/firefox/52.0/releasenotes/