{"id":167905,"date":"2026-04-08T11:11:59","date_gmt":"2026-04-08T09:11:59","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/uyazvimost-vo-flatpak-pozvolyayushhaya-vypolnit-kod-vne-izolirovannogo-okruzheniya"},"modified":"2026-04-08T11:11:59","modified_gmt":"2026-04-08T09:11:59","slug":"uyazvimost-vo-flatpak-pozvolyayushhaya-vypolnit-kod-vne-izolirovannogo-okruzheniya","status":"publish","type":"post","link":"https:\/\/prohoster.info\/en\/blog\/news\/uyazvimost-vo-flatpak-pozvolyayushhaya-vypolnit-kod-vne-izolirovannogo-okruzheniya","title":{"rendered":"Vulnerability in Flatpak allows code execution outside the isolated environment","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"
In a corrective release of the standalone package system Flatpak 1.16.4 published a few hours ago, as well as in the experimental release 1.17.4, a vulnerability (CVE-2026-34078) has been addressed, which allows a malicious or compromised flatpak application to bypass the established sandbox isolation mode, access files in the main system, and execute arbitrary code outside the isolation mode. The issue has been assigned a critical severity level (9.3 out of 10). <\/p>\n
The vulnerability exists in the D-Bus service flatpak-portal, which facilitates the launching of \"portals\" used to provide access to resources in the main environment from isolated applications. The issue arises because the flatpak-portal service allows applications to specify file paths in the sandbox-expose option that, due to lack of proper checks, can be symbolic links pointing to arbitrary parts of the filesystem. <\/p>\n
Before mounting, the service reveals the symbolic link and mounts to the sandbox environment the path it points to, which allows bypassing isolation and gaining read\/write access to files in the host environment. To execute one's code in the system, for example, one could add an auto-start script like \"~\/.bashrc\" or \"~\/.profile\", or modify the file \"~\/.ssh\/authorized_keys\" with SSH keys. <\/p>\n
The status of vulnerability remediation in distributions can be assessed on the following pages (if the page is unavailable, it means the distribution developers have not yet started addressing the issue): Debian, Ubuntu, SUSE, RHEL, Gentoo, Arch, Fedora. As a workaround for protection, one can disable the flatpak-portal service: sudo systemctl --global mask flatpak-portal.service && systemctl --user stop flatpak-portal.service <\/p>\n
In addition to the critical vulnerability, the new release addresses three more security issues: <\/p>\n
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The possibility (CVE-2026-34079) of deleting arbitrary files in the host system's filesystem. The problem arises because flatpak does not check the actual presence of the deleted file in the cache directory when cleaning outdated ld.so cache.\n
The possibility of reading arbitrary files in the context of system-helper on systems with an OCI image repository configured through manipulation with symbolic links.\n
The ability to intervene in processing cancellation requests for applications, allowing one user to prevent another user from stopping the download. <\/ul>\n