The recent update to AppArmor to remedy issues with 3rd-party apps being unable to run on Ubuntu 24.04 LTS (due to its security hardening) inadvertently prevents a fleet of popular Flatpak apps from running either.
The Telegram Desktop, KeePassXC, and Steam clients are among Flatpak apps users have reported issues with, seemingly due to the AppArmor profile tweaks for the Bubblewrap sandboxing tool the prior update introduced.
To be clear: snap, DEB, and binary versions of the software above are not affected, only Flatpak packages installed from stores like Flathub.
But good news: Ubuntu’s developers got to work to identify the cause, aided by sterling investigative efforts from the wider community, and the bug report marked ‘fix committed’ a few hours ago.
A fixed package got added to the proposed repo last night. Usually, packages sit in proposed for a week or so, but this update has been fast-tracked to the updates channel already, so it should be available to install via Software Updater imminently.
The package version with the Flatpak fix is 4.0.1really4.0.0-beta3-0ubuntu0.1, and the change-log notes it “drops /etc/apparmor.d/bwrap-userns-restrict, allowing various Flatpak apps to save files again”.
So if you’ve been frustrated that a few of your favourite Flatpak apps fail to open on Ubuntu 24.04 LTS, you now know why, and that a fix is inbound.