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Fencer Vulns
critical 9.0

CVE-2026-34078 json

Flatpak has a complete sandbox escape leading to host file access and code execution in the host context

published 2026-04-07 7 mo ago modified 2026-07-24 3 mo ago also EUVD-2026-19970

cvss
9.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.7%
EPSS 1.7% chance of exploitation in 30 days, percentile 77%
public exploits
0
none known

Summary

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.

Patch / fix

  • Red Hat Red Hat Enterprise Linux 10 0:1.16.0-9.el10_2.1
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support 0:1.16.0-5.el10_0.2
  • Red Hat Red Hat Enterprise Linux 7 Extended Lifecycle Support 0:1.12.9-3.el7_9
  • Red Hat Red Hat Enterprise Linux 8 0:1.12.9-4.el8_10
  • Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support 0:1.12.9-2.el8_4
  • Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On 0:1.12.9-2.el8_4
  • Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support 0:1.12.9-1.el8_6
  • Red Hat Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On 0:1.12.9-1.el8_6
  • Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service 0:1.12.9-1.el8_8
  • Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions 0:1.12.9-1.el8_8
  • Red Hat Red Hat Enterprise Linux 9 0:1.12.9-4.el9_8.1
  • Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions 0:1.12.7-5.el9_2.1
  • Red Hat Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions 0:1.12.9-3.el9_4.1
  • Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support 0:1.12.9-4.el9_6.1
  • flatpak Debian 12 1.14.10-1~deb12u2
  • flatpak Debian 13 1.16.6-1~deb13u1
  • flatpak Debian 14 1.16.4-1

debian advisories DEBIAN-CVE-2026-34078

  • flatpak Ubuntu Pro 20.04 LTS 1.6.5-0ubuntu0.5+esm1
  • flatpak Ubuntu Pro 22.04 LTS 1.12.7-1ubuntu0.1+esm1
  • flatpak Ubuntu Pro 24.04 LTS 1.14.6-1ubuntu0.1+esm1

ubuntu advisories UBUNTU-CVE-2026-34078

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • flatpak RHEL 10.2 1.16.0-9.el10_2.1
  • flatpak-libs RHEL 10.2 1.16.0-9.el10_2.1
  • flatpak-selinux RHEL 10.2 1.16.0-9.el10_2.1
  • flatpak-session-helper RHEL 10.2 1.16.0-9.el10_2.1
  • flatpak RHEL 9 1.12.9-4.el9_8.1
  • flatpak-libs RHEL 9 1.12.9-4.el9_8.1
  • flatpak-selinux RHEL 9 1.12.9-4.el9_8.1
  • flatpak-session-helper RHEL 9 1.12.9-4.el9_8.1

red hat advisories RHSA-2026:35843RHSA-2026:30901RHSA-2026:25381RHSA-2026:25068RHSA-2026:23418RHSA-2026:23419

  • flatpak SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 1.16.6-150500.3.21.1
  • flatpak SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Desktop Applications 15 SP7 1.16.0-150600.3.9.1
  • flatpak SLES for SAP 15 SP5, SLES 15 SP5-LTSS, SLE High Performance Computing 15 SP5-LTSS +1 more 1.16.0-150500.3.18.1
  • flatpak SLES for SAP 15 SP4, SLES 15 SP4-LTSS, SLE High Performance Computing 15 SP4-LTSS +1 more 1.12.8-150400.3.12.1

suse advisories SUSE-SU-2026:5127-1SUSE-SU-2026:1600-1SUSE-SU-2026:1541-1SUSE-SU-2026:1511-1

  • flatpak openSUSE Tumbleweed 1.16.6-1.1

opensuse advisories openSUSE-SU-2026:10541-1

  • flatpak AlmaLinux 9 1.12.9-4.el9_8.1
  • flatpak-libs AlmaLinux 9 1.12.9-4.el9_8.1
  • flatpak-selinux AlmaLinux 9 1.12.9-4.el9_8.1
  • flatpak-session-helper AlmaLinux 9 1.12.9-4.el9_8.1
  • flatpak AlmaLinux 8 1.12.9-4.el8_10
  • flatpak-libs AlmaLinux 8 1.12.9-4.el8_10
  • flatpak-selinux AlmaLinux 8 1.12.9-4.el8_10
  • flatpak-session-helper AlmaLinux 8 1.12.9-4.el8_10

almalinux advisories ALSA-2026:21755ALSA-2026:21756ALSA-2026:21757

  • flatpak Rocky Linux 9 1.12.9-4.el9_8.1
  • flatpak Rocky Linux 10 1.16.0-9.el10_2.1
  • flatpak Rocky Linux 8 1.12.9-4.el8_10

rocky linux advisories RLSA-2026:21755RLSA-2026:21757RLSA-2026:21756

  • flatpak Alpine 3.24, Alpine 3.23 1.16.4-r0

alpine advisories ALPINE-CVE-2026-34078

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-34078 updated cvss 9.0

flatpak: Flatpak: Arbitrary code execution via crafted symlinks in sandbox-expose options

  • Red Hat CodeReady Linux Builder EUS (v.9.6) flatpak 1.12.9-4.el9_6.1, flatpak-session-helper 1.12.9-4.el9_6.1
    fixed: vendor fix RHSA-2026:23418
  • Red Hat Enterprise Linux AppStream (v. 8) flatpak 1.12.9-4.el8_10, flatpak-libs 1.12.9-4.el8_10, flatpak-selinux 1.12.9-4.el8_10, flatpak-session-helper 1.12.9-4.el8_10
    fixed: vendor fix RHSA-2026:21756
  • Red Hat Enterprise Linux AppStream (v. 9) flatpak 1.12.9-4.el9_8.1, flatpak-libs 1.12.9-4.el9_8.1, flatpak-selinux 1.12.9-4.el9_8.1, flatpak-session-helper 1.12.9-4.el9_8.1
    fixed: vendor fix RHSA-2026:21755
  • Red Hat Enterprise Linux AppStream (v. 10) flatpak 1.16.0-9.el10_2.1, flatpak-libs 1.16.0-9.el10_2.1, flatpak-selinux 1.16.0-9.el10_2.1, flatpak-session-helper 1.16.0-9.el10_2.1
    fixed: vendor fix RHSA-2026:21757
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) flatpak 1.12.9-2.el8_4, flatpak-libs 1.12.9-2.el8_4, flatpak-selinux 1.12.9-2.el8_4, flatpak-session-helper 1.12.9-2.el8_4
    fixed: vendor fix RHSA-2026:30901
  • Red Hat Enterprise Linux AppStream AUS (v.8.6) flatpak 1.12.9-1.el8_6, flatpak-libs 1.12.9-1.el8_6, flatpak-selinux 1.12.9-1.el8_6, flatpak-session-helper 1.12.9-1.el8_6
    fixed: vendor fix RHSA-2026:25381
  • Red Hat Enterprise Linux AppStream E4S (v.8.8) flatpak 1.12.9-1.el8_8, flatpak-libs 1.12.9-1.el8_8, flatpak-selinux 1.12.9-1.el8_8, flatpak-session-helper 1.12.9-1.el8_8
    fixed: vendor fix RHSA-2026:25068
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) flatpak 1.12.7-5.el9_2.1, flatpak-libs 1.12.7-5.el9_2.1, flatpak-selinux 1.12.7-5.el9_2.1, flatpak-session-helper 1.12.7-5.el9_2.1
    fixed: vendor fix RHSA-2026:23419
show 11 more
  • Red Hat Enterprise Linux AppStream E4S (v.9.4) flatpak 1.12.9-3.el9_4.1, flatpak-libs 1.12.9-3.el9_4.1, flatpak-selinux 1.12.9-3.el9_4.1, flatpak-session-helper 1.12.9-3.el9_4.1
    fixed: vendor fix RHSA-2026:23417
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) flatpak 1.16.0-5.el10_0.2, flatpak-libs 1.16.0-5.el10_0.2, flatpak-selinux 1.16.0-5.el10_0.2, flatpak-session-helper 1.16.0-5.el10_0.2
    fixed: vendor fix RHSA-2026:23420
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) flatpak 1.12.9-4.el9_6.1, flatpak-libs 1.12.9-4.el9_6.1, flatpak-selinux 1.12.9-4.el9_6.1, flatpak-session-helper 1.12.9-4.el9_6.1
    fixed: vendor fix RHSA-2026:23418
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) flatpak 1.12.9-2.el8_4, flatpak-libs 1.12.9-2.el8_4, flatpak-selinux 1.12.9-2.el8_4, flatpak-session-helper 1.12.9-2.el8_4
    fixed: vendor fix RHSA-2026:30901
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6) flatpak 1.12.9-1.el8_6, flatpak-libs 1.12.9-1.el8_6, flatpak-selinux 1.12.9-1.el8_6, flatpak-session-helper 1.12.9-1.el8_6
    fixed: vendor fix RHSA-2026:25381
  • Red Hat Enterprise Linux AppStream TUS (v.8.8) flatpak 1.12.9-1.el8_8, flatpak-libs 1.12.9-1.el8_8, flatpak-selinux 1.12.9-1.el8_8, flatpak-session-helper 1.12.9-1.el8_8
    fixed: vendor fix RHSA-2026:25068
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) flatpak 1.12.9-4.el9_8.1, flatpak-session-helper 1.12.9-4.el9_8.1
    fixed: vendor fix RHSA-2026:21755
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) flatpak-devel 1.16.0-9.el10_2.1, flatpak-debuginfo 1.16.0-9.el10_2.1, flatpak-debugsource 1.16.0-9.el10_2.1, flatpak-libs-debuginfo 1.16.0-9.el10_2.1, flatpak-tests-debuginfo 1.16.0-9.el10_2.1, flatpak-session-helper-debuginfo 1.16.0-9.el10_2.1
    fixed: vendor fix RHSA-2026:21757
  • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) flatpak-devel 1.16.0-5.el10_0.2, flatpak-debuginfo 1.16.0-5.el10_0.2, flatpak-debugsource 1.16.0-5.el10_0.2, flatpak-libs-debuginfo 1.16.0-5.el10_0.2, flatpak-tests-debuginfo 1.16.0-5.el10_0.2, flatpak-session-helper-debuginfo 1.16.0-5.el10_0.2
    fixed: vendor fix RHSA-2026:23420
  • Red Hat Enterprise Linux CRB (v. 8) flatpak 1.12.9-4.el8_10, flatpak-session-helper 1.12.9-4.el8_10
    fixed: vendor fix RHSA-2026:21756
  • Red Hat Enterprise Linux Server (v. 7 ELS) flatpak 1.12.9-3.el7_9, flatpak-libs 1.12.9-3.el7_9 Red Hat Enterprise Linux Server Optional (v. 7 ELS) flatpak-builder 1.0.0-16.el7_9
    fixed: vendor fix RHSA-2026:35843

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
7 mo ago

Exploit prediction

1.71% chance of exploitation in the next 30 days, higher than 77% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 4.0 9.3 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
CISA ADP 3.1 9.0 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
CNA 4.0 9.3 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:X
NVD 3.1 10.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CNA 3.1 9.0 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

Affected products

  • flatpak flatpak
  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 7 Extended Lifecycle Support
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
  • Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On
  • Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
  • Red Hat Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On
  • Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service
  • Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support

Classification

Weakness
  • CWE-61 UNIX Symbolic Link (Symlink) Following
  • CWE-59 Improper Link Resolution Before File Access

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.