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Fencer Intel
high 7.4

CVE-2026-90616 json

CVE-2026-90616: Flatpak sandbox escape with full host filesystem access

published 3mo ago modified last mo. also EUVD-2026-76911 , GHSA-8688-9x26-hhxj

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository flatpak/flatpak. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
7.4
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 7%
public exploits
0
none known

Summary

In Flatpak before 1.18.1, a malicious sandboxed app can obtain arbitrary read and write access to files on the host, which can be escalated to arbitrary code execution on the host, a different vulnerability than CVE-2026-76925. Flatpak creates a few app data directories (e.g., /var/cache, /var/data, /var/config, and /var/tmp) in every sandbox on every app launch where, in some cases, components of the path are attacker-controlled. Missing symlink protection can redirect the directories. Some of these directories are bind-mounted by Flatpak by passing the path (e.g., /home/user/.var/app/APP_ID/cache/tmp), which contains attacker-controlled directories (tmp) to bwrap --bind SRC DST. bwrap passes the path on to the kernel, which then follows symlinks. A malicious symlink can point to arbitrary locations on the host and it will become mounted inside the sandbox.

Patch / fix

  • Flatpak Flatpak 1.18.1
  • flatpak Debian 13 1.16.6-1~deb13u3
  • flatpak Debian 14 1.18.1-1

debian advisories DEBIAN-CVE-2026-90616

  • flatpak RHEL 8 1.12.9-7.el8_10
  • flatpak-libs RHEL 8 1.12.9-7.el8_10
  • flatpak-selinux RHEL 8 1.12.9-7.el8_10
  • flatpak-session-helper RHEL 8 1.12.9-7.el8_10
  • flatpak RHEL 10.2 1.16.0-9.el10_2.4
  • flatpak-libs RHEL 10.2 1.16.0-9.el10_2.4
  • flatpak-selinux RHEL 10.2 1.16.0-9.el10_2.4
  • flatpak-session-helper RHEL 10.2 1.16.0-9.el10_2.4

red hat advisories RHSA-2026:80687RHSA-2026:80498RHSA-2026:80497

  • 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 1.16.6-150600.3.12.1
  • flatpak SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 1.4.2-3.15.1

suse advisories SUSE-SU-2026:5127-1SUSE-SU-2026:4944-1SUSE-SU-2026:4610-1

  • flatpak AlmaLinux 9 1.12.9-4.el9_8.4
  • flatpak-libs AlmaLinux 9 1.12.9-4.el9_8.4
  • flatpak-selinux AlmaLinux 9 1.12.9-4.el9_8.4
  • flatpak-session-helper AlmaLinux 9 1.12.9-4.el9_8.4
  • flatpak AlmaLinux 10 1.16.0-9.el10_2.4
  • flatpak-libs AlmaLinux 10 1.16.0-9.el10_2.4
  • flatpak-selinux AlmaLinux 10 1.16.0-9.el10_2.4
  • flatpak-session-helper AlmaLinux 10 1.16.0-9.el10_2.4

almalinux advisories ALSA-2026:80497ALSA-2026:80498ALSA-2026:80687

  • flatpak Rocky Linux 10 1.16.0-9.el10_2.4
  • flatpak Rocky Linux 9 1.12.9-4.el9_8.4
  • flatpak Rocky Linux 8 1.12.9-7.el8_10

rocky linux advisories RLSA-2026:80498RLSA-2026:80497RLSA-2026:80687

Is CVE-2026-90616 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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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-2026-90616 updated cvss 7.8

flatpak: Flatpak: Arbitrary code execution via missing symlink protection

  • Red Hat CodeReady Linux Builder EUS (v.9.6) flatpak 1.12.9-4.el9_6.5, flatpak-session-helper 1.12.9-4.el9_6.5
    fixed: vendor fix RHSA-2026:89733
  • Red Hat Enterprise Linux AppStream (v. 8) flatpak 1.12.9-7.el8_10, flatpak-libs 1.12.9-7.el8_10, flatpak-selinux 1.12.9-7.el8_10, flatpak-session-helper 1.12.9-7.el8_10
    fixed: vendor fix RHSA-2026:80687
  • Red Hat Enterprise Linux AppStream (v. 9) flatpak 1.12.9-4.el9_8.4, flatpak 1.12.9-6.el9_9.5, flatpak-libs 1.12.9-4.el9_8.4, flatpak-libs 1.12.9-6.el9_9.5, flatpak-selinux 1.12.9-4.el9_8.4, flatpak-selinux 1.12.9-6.el9_9.5, +2 more
    fixed: vendor fix RHSA-2026:80497
  • Red Hat Enterprise Linux AppStream (v. 10) flatpak 1.16.0-9.el10_2.4, flatpak 1.18.0-2.el10_3.4, flatpak-libs 1.16.0-9.el10_2.4, flatpak-libs 1.18.0-2.el10_3.4, flatpak-selinux 1.16.0-9.el10_2.4, flatpak-selinux 1.18.0-2.el10_3.4, +2 more
    fixed: vendor fix RHSA-2026:80498
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) flatpak 1.12.9-2.el8_4.1, flatpak-libs 1.12.9-2.el8_4.1, flatpak-selinux 1.12.9-2.el8_4.1, flatpak-session-helper 1.12.9-2.el8_4.1
    fixed: vendor fix RHSA-2026:98112
  • Red Hat Enterprise Linux AppStream AUS (v.8.6) flatpak 1.12.9-1.el8_6.1, flatpak-libs 1.12.9-1.el8_6.1, flatpak-selinux 1.12.9-1.el8_6.1, flatpak-session-helper 1.12.9-1.el8_6.1
    fixed: vendor fix RHSA-2026:95493
  • Red Hat Enterprise Linux AppStream E4S (v.8.8) flatpak 1.12.9-1.el8_8.1, flatpak-libs 1.12.9-1.el8_8.1, flatpak-selinux 1.12.9-1.el8_8.1, flatpak-session-helper 1.12.9-1.el8_8.1
    fixed: vendor fix RHSA-2026:98127
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) flatpak 1.12.7-5.el9_2.5, flatpak-libs 1.12.7-5.el9_2.5, flatpak-selinux 1.12.7-5.el9_2.5, flatpak-session-helper 1.12.7-5.el9_2.5
    fixed: vendor fix RHSA-2026:92369
show 11 more
  • Red Hat Enterprise Linux AppStream E4S (v.9.4) flatpak 1.12.9-3.el9_4.5, flatpak-libs 1.12.9-3.el9_4.5, flatpak-selinux 1.12.9-3.el9_4.5, flatpak-session-helper 1.12.9-3.el9_4.5
    fixed: vendor fix RHSA-2026:90364
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) flatpak 1.16.0-5.el10_0.6, flatpak-libs 1.16.0-5.el10_0.6, flatpak-selinux 1.16.0-5.el10_0.6, flatpak-session-helper 1.16.0-5.el10_0.6
    fixed: vendor fix RHSA-2026:92221
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) flatpak 1.12.9-4.el9_6.5, flatpak-libs 1.12.9-4.el9_6.5, flatpak-selinux 1.12.9-4.el9_6.5, flatpak-session-helper 1.12.9-4.el9_6.5
    fixed: vendor fix RHSA-2026:89733
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) flatpak 1.12.9-2.el8_4.1, flatpak-libs 1.12.9-2.el8_4.1, flatpak-selinux 1.12.9-2.el8_4.1, flatpak-session-helper 1.12.9-2.el8_4.1
    fixed: vendor fix RHSA-2026:98112
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.6) flatpak 1.12.9-1.el8_6.1, flatpak-libs 1.12.9-1.el8_6.1, flatpak-selinux 1.12.9-1.el8_6.1, flatpak-session-helper 1.12.9-1.el8_6.1
    fixed: vendor fix RHSA-2026:95493
  • Red Hat Enterprise Linux AppStream TUS (v.8.8) flatpak 1.12.9-1.el8_8.1, flatpak-libs 1.12.9-1.el8_8.1, flatpak-selinux 1.12.9-1.el8_8.1, flatpak-session-helper 1.12.9-1.el8_8.1
    fixed: vendor fix RHSA-2026:98127
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) flatpak 1.12.9-4.el9_8.4, flatpak 1.12.9-6.el9_9.5, flatpak-session-helper 1.12.9-4.el9_8.4, flatpak-session-helper 1.12.9-6.el9_9.5
    fixed: vendor fix RHSA-2026:80497
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) flatpak-devel 1.16.0-9.el10_2.4, flatpak-devel 1.18.0-2.el10_3.4, flatpak-debuginfo 1.16.0-9.el10_2.4, flatpak-debuginfo 1.18.0-2.el10_3.4, flatpak-debugsource 1.16.0-9.el10_2.4, flatpak-debugsource 1.18.0-2.el10_3.4, +6 more
    fixed: vendor fix RHSA-2026:80498
  • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) flatpak-devel 1.16.0-5.el10_0.6, flatpak-debuginfo 1.16.0-5.el10_0.6, flatpak-debugsource 1.16.0-5.el10_0.6, flatpak-libs-debuginfo 1.16.0-5.el10_0.6, flatpak-tests-debuginfo 1.16.0-5.el10_0.6, flatpak-session-helper-debuginfo 1.16.0-5.el10_0.6
    fixed: vendor fix RHSA-2026:92221
  • Red Hat Enterprise Linux CRB (v. 8) flatpak 1.12.9-7.el8_10, flatpak-session-helper 1.12.9-7.el8_10
    fixed: vendor fix RHSA-2026:80687
  • Red Hat Enterprise Linux Server (v. 7 ELS) flatpak 1.12.9-6.el7_9, flatpak-libs 1.12.9-6.el7_9 Red Hat Enterprise Linux Server Optional (v. 7 ELS) flatpak-builder 1.0.0-18.el7_9
    fixed: vendor fix RHSA-2026:99010

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
no
Technical impact
total
Assessed
last mo.

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 7.4 CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Flatpak Flatpak

Classification

Weakness
  • CWE-61 UNIX Symbolic Link (Symlink) Following

References

Sources

Fencer Intel 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.

The maintainers of flatpak/flatpak published their own advisory on GitHub. Reviewed sources take precedence over it.

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