It was distributed on Monday Flatpak 1.18.4security update closing you are vulnerability in the application distribution and sandboxing system for Linux. The two that touch the filesystem require that you have a malicious app installed. CVE-2026-97024 allows privileged overwriting of arbitrary files, with an empty file or with a symbolic link to /run/host/monitor/resolv.confWhile CVE-2026-97023 allows privileged deletion of arbitrary files. The release notes also report a strengthening of defenses against symlink traversal, linked to these two flaws.
Two other fixes concern data exposed to other users of the same machine. By downloading apps or runtimes from an OCI repository that requires authentication, the authentication token was visible to other users (CVE-2026-97025). The temporary directories of the repositories in /var/tmp/flatpak-cache-* now have more restrictive permits (CVE-2026-97026).
The last two vulnerabilities concern denial of service. D-Bus .desktop files and .service files are now filtered based on a list of allowed fields, to avoid denial of service and unwanted interactions with host services (CVE-2026-97027). With CVE-2026-97029 an app could send signals to a process group that includes a parent process external to the app, and terminating that process would bring down the desktop environment.
The reports bear the name of Sebastian Wick for the two filesystem vulnerabilities, of AISLE in collaboration with Red Hat for the two on the repositories, of Markus Göllnitz for the filtering of .desktop and D-Bus files and of Guthrie Armstrong, of Coalition, Inc., for the signals. Minor fixes include updating Meson subproject wraps for projects normally sourced from the host system.
