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Fencer Vulns
high 8.8

CVE-2026-94422 json

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

published 2026-10-02 38 d ago modified 2026-10-24 16 d ago also EUVD-2026-91646

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 42%
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

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

rocky linux advisories RLSA-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

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
    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
    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
37 d ago

Exploit prediction

0.50% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-08).

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

  • 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 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.