User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:109.0) Gecko/20100101 Firefox/112.0

Steps to reproduce:

1. Open Firefox Flatpak
2. Navigate to Facebook, TrueNAS forums (some other website are affected too but I don't remember all of them)

Actual results:

Texts do not render at all

Expected results:

All text should render correctly

The Bugbug bot thinks this bug should belong to the 'Core::Widget: Gtk' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

CLI lanch log :
Gtk-Message: 12:30:52.248: Failed to load module "canberra-gtk-module"
Gtk-Message: 12:30:52.248: Failed to load module "canberra-gtk-module"
ATTENTION: default value of option mesa_glthread overridden by environment.
ATTENTION: default value of option mesa_glthread overridden by environment.
ATTENTION: default value of option mesa_glthread overridden by environment.
[ERROR glean_core] Error setting metrics feature config: Json(Error("EOF while parsing a value", line: 1, column: 0))

Snapshot of https://html5test.com/

Screenshot of html5test.com (using Spectacle)

Another screenshot

Same issue here, Firefox 112.0.1 (64 bit) flatpak.
Disabling site font (browser.display.use_document_fonts=0) shows text.
Using platform font (i.e.: serif) shows text.
Disabling hardware acceleration does not fix the issue.

Maybe some issue with specific font type/format?
I noticed that using Firefox to capture pages shows all text, I used Spectacle to show the issue.

Operating System: Kubuntu 22.10
KDE Plasma Version: 5.25.5
KDE Frameworks Version: 5.98.0
Qt Version: 5.15.6
Kernel Version: 5.19.0-38-generic (64-bit)
Graphics Platform: X11
Processors: 16 × AMD Ryzen 7 5700X 8-Core Processor
Memory: 31.3 GiB of RAM
Graphics Processor: NVIDIA GeForce GTX 1060 3GB/PCIe/SSE2
Manufacturer: ASUS

Same issue using nouveau driver instead of NVIDIA.

Hum... Something strange I noticed is that only AppArmor based distro seem to be affected. I installed openSUSE MicroOS, which is basically the same as Tumbleweed except it uses SELinux instead, and it works. May just be a coincidence, but may also be a lead. Can anyone try on Fedora?

Tested on a different PC, Kubuntu, X11, Flatpak... It works as expected.

Similar discussion: https://www.reddit.com/r/firefox/comments/12se3ey/css_rendering_profile_issues_with_firefox_112/

Seem to be a duplicate of this bug : https://bugzilla.mozilla.org/show_bug.cgi?id=1827950

Updating to the latest Firefox beta (113.0b5) resolves it (albeit with strange looking fonts)

(In reply to egeorget from comment #11)

Seem to be a duplicate of this bug : https://bugzilla.mozilla.org/show_bug.cgi?id=1827950

Removing the Ubuntu package xfonts-100dpi fixes the issue!
Thank you.