Hi, Flatpak releases 1.16.4 and 1.17.4 are documented to include 4 security fixes, including one for a critical severity issue. Flatpak releases 1.16.5 and 1.17.5 fix regressions caused by the critical security fix:
https://github.com/flatpak/flatpak/releases The security page: https://github.com/flatpak/flatpak/security lists the 4 security issues as follows (I reversed the order here): > CVE-2026-34078: Complete sandbox escape leading to host file access and code > execution in the host context > GHSA-cc2q-qc34-jprg published yesterday by swick > Critical > > CVE-2026-34079: Arbitrary file deletion on the host filesystem > GHSA-p29x-r292-46pp published yesterday by swick > Moderate > > Arbitrary read-access to files in the system-helper context > GHSA-2fxp-43j9-pwvc published yesterday by swick > Low > > flatpak-system-helper: cross-user CancelPull orphans another user's ongoing > pull > GHSA-89xm-3m96-w3jg published yesterday by swick > Low Here they are individually: https://github.com/flatpak/flatpak/security/advisories/GHSA-cc2q-qc34-jprg > CVE-2026-34078: Complete sandbox escape leading to host file access and code > execution in the host context > Critical > swick published GHSA-cc2q-qc34-jprg yesterday > > Affected versions > <1.16.4 > Patched versions > 1.16.4 > > Impact > > Every Flatpak app is able to read and write arbitrary files on the host and > execute code in the host context. > > Description > > The Flatpak portal accepts paths in the sandbox-expose options which can be > app-controlled symlinks pointing at arbitrary paths. Flatpak run mounts the > resolved host path in the sandbox. This gives apps access to all host files > and can be used as a primitive to gain code execution in the host context. > > Patches > > The issue has been patched in version 1.16.4 and will be patched in the > upcoming version 1.18.0. > > Mitigations > > Disabling the Flatpak Portal mitigates the issue but can result in > misbehaving apps. > > sudo systemctl --global mask flatpak-portal.service && systemctl --user stop > flatpak-portal.service > > Credits > > Reported by Codean Labs https://github.com/flatpak/flatpak/security/advisories/GHSA-p29x-r292-46pp > CVE-2026-34079: Arbitrary file deletion on the host filesystem > Moderate > swick published GHSA-p29x-r292-46pp yesterday > > Affected versions > <1.16.4 > Patched versions > 1.16.4 > > Impact > > Every Flatpak app is able to delete arbitrary files on the host. > > Description > > The caching for ld.so removes outdated cache files without properly checking > that the app controlled path to the outdated cache is in the cache directory. > > Patches > > The issue has been patched in version 1.16.4 and will be patched in the > upcoming version 1.18.0. > > Mitigations > > No know mitigation other than updating > > Credits > > Reported by Codean Labs https://github.com/flatpak/flatpak/security/advisories/GHSA-2fxp-43j9-pwvc > Arbitrary read-access to files in the system-helper context > Low > swick published GHSA-2fxp-43j9-pwvc yesterday > > Affected versions > <1.16.4 > Patched versions > 1.16.4 > > Impact > > A malicious user can get read-access to files in the system-helper context if > a system OCI repository is configured. > > Description > > The OCI code paths in the system helper will follow symlinks when importing > OCI images which are under the user's control. > > Patches > > The issue has been patched in version 1.16.4 and will be patched in the > upcoming version 1.18.0. > > Mitigations > > Remove all OCI system remotes. > > Credits > > @smcv https://github.com/flatpak/flatpak/security/advisories/GHSA-89xm-3m96-w3jg > flatpak-system-helper: cross-user CancelPull orphans another user's ongoing > pull > Low > swick published GHSA-89xm-3m96-w3jg yesterday > > Affected versions > <1.16.4 > Patched versions > 1.16.4 > > Impact > > Ongoing pulls cannot be stopped. > > Description > > By calling org.freedesktop.Flatpak.SystemHelper.CancelPull on another user's > pull, the pull does not get cancelled but removed from internal tracking, > making it impossible to stop it. > > Patches > > The issue has been patched in version 1.16.4 and will be patched in the > upcoming version 1.18.0. > > Mitigations > > No known mitigation other than updating. > > Credits > > Asim Viladi Oglu Manizada Alexander
