[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-ID: <20260409003256.GA12812@openwall.com>
Date: Thu, 9 Apr 2026 02:32:56 +0200
From: Solar Designer <solar@...nwall.com>
To: oss-security@...ts.openwall.com
Subject: 4 security fixes in Flatpak, including critical CVE-2026-34078: Complete sandbox escape leading to host file access and code execution in the host context
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
Powered by blists - more mailing lists
Please check out the
Open Source Software Security Wiki, which is counterpart to this
mailing list.
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
