Skip to content
Fencer Vulns
critical 9.8

CVE-2026-96276 json

Flatpak: flatpak: arbitrary write in host context via flatpak build-init

published 2026-09-23 46 d ago modified 2026-11-06 3 d ago also EUVD-2026-85343

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 38%
public exploits
0
none known

Summary

If a malicious SDK container declares an extension point with a crafted `directory` path, and a developer runs `flatpak build-init --writable-sdk --sdk-extension` with that SDK, attacker-chosen files could be written outside the working directory, since the target path is resolved via a function that allows `..` traversal.

Patch / fix

  • flatpak Debian 13 1.16.6-1~deb13u2
  • flatpak Debian 14 1.18.1-1

debian advisories DEBIAN-CVE-2026-96276

  • 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

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-2026-96276 updated cvss 6.5

flatpak: flatpak: Arbitrary write in host context via flatpak build-init

  • Red Hat Enterprise Linux 7 flatpak, flatpak-libs, flatpak-builder, flatpak 1.18.0-1.el10 Red Hat Enterprise Linux 8 flatpak, flatpak-libs, flatpak-selinux, flatpak 1.18.0-1.el10, flatpak-session-helper Red Hat Enterprise Linux 9 flatpak, flatpak-libs, flatpak-selinux, flatpak 1.18.0-1.el10, flatpak-session-helper Red Hat Enterprise Linux 10 flatpak 1.18.0-1.el10
    affected: workaround, no fix available “Avoid using an non-trusted SDK for development/compilation.”

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
46 d ago

Exploit prediction

0.44% chance of exploitation in the next 30 days, higher than 38% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
CISA ADP 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

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.