CRITICAL9.3
Flatpak is a Linux application sandboxing and distribution framework. Prior to 1.16.4, 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. This vulnerability is fixed in 1.16.4.
CVSS 3.xCRITICAL 10.0
CVSS:3.x/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:HCVSS 4.0CRITICAL 9.3
CVSS:4.0/CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XReferences
- https://github.com/flatpak/flatpak/security/advisories/GHSA-cc2q-qc34-jprg
- http://www.openwall.com/lists/oss-security/2026/04/09/8
- http://www.openwall.com/lists/oss-security/2026/04/10/14
- https://access.redhat.com/errata/RHSA-2026:21755
- https://access.redhat.com/errata/RHSA-2026:21756
- https://access.redhat.com/errata/RHSA-2026:21757
- https://access.redhat.com/errata/RHSA-2026:23417
- https://access.redhat.com/errata/RHSA-2026:23418
- https://access.redhat.com/errata/RHSA-2026:23419
- https://access.redhat.com/errata/RHSA-2026:23420
- https://access.redhat.com/errata/RHSA-2026:25068
- https://access.redhat.com/errata/RHSA-2026:25381
- https://access.redhat.com/errata/RHSA-2026:30901
- https://access.redhat.com/security/cve/CVE-2026-34078
- https://bugzilla.redhat.com/show_bug.cgi?id=2456276
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-34078.json