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Fencer Intel
high 8.8

CVE-2026-94422 json

xdg-dbus-proxy: message filtering bypass via reply serial allows sandbox escape

published last mo. modified 19d ago also EUVD-2026-91646 , GHSA-2cgv-pwcq-wvpq

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository flatpak/xdg-dbus-proxy. 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
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 43%
public exploits
0
none known

Summary

An incorrect implementation of message filtering in xdg-dbus-proxy versions before 0.1.9 allows an attacker to bypass the intended message filtering on the D-Bus session bus by setting a reply serial number on non-reply messages. A malicious or compromised Flatpak app could use this to achieve arbitrary code execution outside its sandbox. xdg-dbus-proxy was designed to be part of the sandbox boundary for Flatpak, but it is released as a separate project and is sometimes used by other app frameworks such as Firejail.

Patch / fix

  • flatpak xdg-dbus-proxy 0.1.9
  • Fedora Fedora 0.1.9
  • xdg-dbus-proxy Debian 12 0.1.4-3+deb12u2
  • xdg-dbus-proxy Debian 13 0.1.6-1+deb13u3
  • xdg-dbus-proxy Debian 14 0.1.9-1

debian advisories DEBIAN-CVE-2026-94422

  • xdg-dbus-proxy openSUSE Tumbleweed 0.1.9-1.1

opensuse advisories openSUSE-SU-2026:11913-1

  • xdg-dbus-proxy AlmaLinux 9 0.1.3-1.el9_8.1
  • xdg-dbus-proxy AlmaLinux 10 0.1.5-4.el10_2.1

almalinux advisories ALSA-2026:90522ALSA-2026:90523

  • xdg-dbus-proxy Rocky Linux 9 0.1.3-1.el9_8.1
  • xdg-dbus-proxy Rocky Linux 10 0.1.5-4.el10_2.1

rocky linux advisories RLSA-2026:98530RLSA-2026:90523RLSA-2026:90522

  • xdg-dbus-proxy Alpine 3.24 0.1.9-r0

alpine advisories ALPINE-CVE-2026-94422

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

Is CVE-2026-94422 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.

Check with Fencer

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-2026-94422 updated cvss 8.8

xdg-dbus-proxy: xdg-dbus-proxy: message filtering bypass via reply serial allows sandbox escape

  • Red Hat Enterprise Linux AppStream (v. 9) xdg-dbus-proxy 0.1.3-1.el9_8.1, xdg-dbus-proxy 0.1.3-1.el9_9.1
    fixed: vendor fix “Avoid running untrusted Flatpak apps and avoid running untrusted apps via other frameworks that use xdg-dbus-proxy.” RHSA-2026:90522
  • Red Hat Enterprise Linux AppStream (v. 10) xdg-dbus-proxy 0.1.5-4.el10_2.1, xdg-dbus-proxy 0.1.5-4.el10_3.1
    fixed: vendor fix “Avoid running untrusted Flatpak apps and avoid running untrusted apps via other frameworks that use xdg-dbus-proxy.” RHSA-2026:90523
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) xdg-dbus-proxy 0.1.3-1.el9_2.1
    fixed: vendor fix “Avoid running untrusted Flatpak apps and avoid running untrusted apps via other frameworks that use xdg-dbus-proxy.” RHSA-2026:91624
  • Red Hat Enterprise Linux AppStream E4S (v.9.4) xdg-dbus-proxy 0.1.3-1.el9_4.1
    fixed: vendor fix “Avoid running untrusted Flatpak apps and avoid running untrusted apps via other frameworks that use xdg-dbus-proxy.” RHSA-2026:91623
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) xdg-dbus-proxy 0.1.5-4.el10_0.1
    fixed: vendor fix “Avoid running untrusted Flatpak apps and avoid running untrusted apps via other frameworks that use xdg-dbus-proxy.” RHSA-2026:91626
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) xdg-dbus-proxy 0.1.3-1.el9_6.1
    fixed: vendor fix “Avoid running untrusted Flatpak apps and avoid running untrusted apps via other frameworks that use xdg-dbus-proxy.” RHSA-2026:91625

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

0.50% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/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

Affected products

  • flatpak xdg-dbus-proxy
  • Fedora Fedora
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Enterprise Linux 10

Classification

Weakness
  • CWE-290 Authentication Bypass by Spoofing

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/xdg-dbus-proxy published their own advisory on GitHub. Reviewed sources take precedence over it.