CVE-2026-34078

critical

Description

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.

References

http://www.openwall.com/lists/oss-security/2026/04/10/14

http://www.openwall.com/lists/oss-security/2026/04/09/8

https://www.helpnetsecurity.com/2026/04/16/tails-vulnerability-expose-saved-files/

https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-34078.json

https://github.com/flatpak/flatpak/security/advisories/GHSA-cc2q-qc34-jprg

https://bugzilla.redhat.com/show_bug.cgi?id=2456276

https://access.redhat.com/security/cve/CVE-2026-34078

https://access.redhat.com/errata/RHSA-2026:35843

https://access.redhat.com/errata/RHSA-2026:30901

https://access.redhat.com/errata/RHSA-2026:25381

https://access.redhat.com/errata/RHSA-2026:25068

https://access.redhat.com/errata/RHSA-2026:23420

https://access.redhat.com/errata/RHSA-2026:23419

https://access.redhat.com/errata/RHSA-2026:23418

https://access.redhat.com/errata/RHSA-2026:23417

https://access.redhat.com/errata/RHSA-2026:21757

https://access.redhat.com/errata/RHSA-2026:21756

https://access.redhat.com/errata/RHSA-2026:21755

Details

Source: Mitre, NVD

Published: 2026-04-07

Updated: 2026-07-06

Risk Information

CVSS v2

Base Score: 10

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

Severity: Critical

CVSS v3

Base Score: 10

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Severity: Critical

CVSS v4

Base Score: 9.3

Vector: 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

Severity: Critical

EPSS

EPSS: 0.00155