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OpenAdvisories
Medium · 6.5 CVE-2026-96276 EUVD-2026-85343

Flatpak: flatpak: arbitrary write in host context via flatpak build-init

Published Sep 23, 2026 · Updated Nov 6, 2026 · Assigned by redhat

Description

If a malicious SDK container declares an extension point with a crafted `directory` path, and a developer runs `flatpak build-init --writable-sdk --sdk-extension` with that SDK, attacker-chosen files could be written outside the working directory, since the target path is resolved via a function that allows `..` traversal.

Affected products

VendorProductAffectedFixed
Red Hat Red Hat Enterprise Linux 10 — —
Red Hat Red Hat Enterprise Linux 7 — —
Red Hat Red Hat Enterprise Linux 8 — —
Red Hat Red Hat Enterprise Linux 9 — —

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 flatpak 1.18.1-1 —
Debian 13 flatpak 1.16.6-1~deb13u2 —
Debian 12 flatpak No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 26.04 LTS flatpak No fix yet —
Show 4 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu Pro 24.04 LTS flatpak No fix yet —
Ubuntu Pro 22.04 LTS flatpak No fix yet —
Ubuntu Pro 20.04 LTS flatpak No fix yet —
Ubuntu Pro 18.04 LTS flatpak No fix yet —
ReleasePackageFixed inAdvisory
SLES 15 SP7 flatpak 1.16.6-150600.3.12.1 SUSE-SU-2026:4944-1
SLES 15 SP6 flatpak 1.16.6-150600.3.12.1 SUSE-SU-2026:4944-1
SLES 15 SP5 flatpak 1.16.6-150500.3.21.1 SUSE-SU-2026:5127-1
SLES 12 SP5 flatpak 1.4.2-3.15.1 SUSE-SU-2026:4610-1
Show 3 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
SLES for SAP 15 SP6 flatpak 1.16.6-150600.3.12.1 SUSE-SU-2026:4944-1
SLES for SAP 15 SP5 flatpak 1.16.6-150500.3.21.1 SUSE-SU-2026:5127-1
SLE HPC 15 SP5 flatpak 1.16.6-150500.3.21.1 SUSE-SU-2026:5127-1

Advisories 3

References