Flatpak 1.18.4 has been released as a security-focused update to the popular application sandboxing and distribution framework for Linux, addressing six newly disclosed vulnerabilities along with several related hardening improvements.
Among the most important fixes is CVE-2026-97024, which could allow a malicious Flatpak application during installation to overwrite arbitrary files with either an empty file or a symlink. A related issue, CVE-2026-97023, could be abused to delete arbitrary files with elevated privileges.
The release also fixes CVE-2026-97025, an issue affecting authenticated OCI repositories. Flatpak now ensures authentication tokens used when downloading applications or runtimes are not exposed to other local users. CVE-2026-97026 is addressed by restricting permissions on temporary repository directories under /var/tmp/flatpak-cache-*.
Another fix, tracked as CVE-2026-97027, introduces stricter filtering of .desktop and D-Bus .service files against an allowlist of permitted fields. According to the developers, this prevents denial-of-service scenarios as well as unintended interactions with services running on the host system.
Flatpak 1.18.4 also resolves CVE-2026-97029, which could allow an application to send signals to a process group containing a parent process outside its sandbox. In certain circumstances, this could result in denial of service by terminating the user’s desktop environment.
Beyond those six vulnerabilities, the update refreshes the bundled xdg-dbus-proxy fallback to version 0.1.9, fixing CVE-2026-93676 and CVE-2026-94422. Flatpak also received additional protection against symlink traversal related to CVE-2026-97023 and CVE-2026-97024.
Finally, given the number and nature of the security fixes included, users are advised to install the update as soon as it becomes available through their Linux distribution’s repositories.
For more details, see the changelog.
