Vulnerability · Published Oct 2, 2026 · Assigned by redhat
CVE-2026-94422xdg-dbus-proxy: message filtering bypass via reply serial allows sandbox escape
High 8.8
In plain English
A high-severity authentication bypass by spoofing in xdg-dbus-proxy. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | xdg-dbus-proxy | 0.1.5-4.el10_2.1 | ALSA-2026:90523 |
| AlmaLinux:9 | xdg-dbus-proxy | 0.1.3-1.el9_8.1 | ALSA-2026:90522 |
| Alpine:v3.24 | xdg-dbus-proxy | 0.1.9-r0 | ALPINE-CVE-2026-94422 |
| Debian:12 | xdg-dbus-proxy | 0.1.4-3+deb12u2 | DEBIAN-CVE-2026-94422 |
| Debian:13 | xdg-dbus-proxy | 0.1.6-1+deb13u3 | DEBIAN-CVE-2026-94422 |
| Debian:14 | xdg-dbus-proxy | 0.1.9-1 | DEBIAN-CVE-2026-94422 |
| Rocky Linux:10 | xdg-dbus-proxy | 0:0.1.5-4.el10_2.1 | RLSA-2026:90523 |
| Rocky Linux:9 | xdg-dbus-proxy | 0:0.1.3-1.el9_8.1 | RLSA-2026:90522 |
| Ubuntu:22.04:LTS | xdg-dbus-proxy | no fix listed | UBUNTU-CVE-2026-94422 |
| Ubuntu:24.04:LTS | xdg-dbus-proxy | no fix listed | UBUNTU-CVE-2026-94422 |
| Ubuntu:26.04:LTS | xdg-dbus-proxy | no fix listed | UBUNTU-CVE-2026-94422 |
| Ubuntu:26.10 | xdg-dbus-proxy | no fix listed | UBUNTU-CVE-2026-94422 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| xdg-dbus-proxy | 0 – before 0.1.9 | |
| Fedora | Fedora | 0 – before 0.1.9 |
| Red Hat | Red Hat Enterprise Linux 9 | see references |
| Red Hat | Red Hat Enterprise Linux 10 | see references |
Weakness: CWE-290 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
References
- https://access.redhat.com/security/cve/CVE-2026-94422 vendor-advisory
- https://github.com/flatpak/xdg-dbus-proxy/security/advisories/GHSA-2cgv-pwcq-wvpq third-party-advisory
- https://github.com/flatpak/xdg-dbus-proxy/commit/e5702fca4dba9600721921fbca2dbc39dc5ca400 patch
- https://github.com/flatpak/xdg-dbus-proxy/commit/fc027f759316fb2a6c45648200b6f100202eb84e patch
- https://github.com/flatpak/xdg-dbus-proxy/commit/e4465a0dfe96da3b39929a30a1ac3a22b16223e3 patch
- https://bugzilla.redhat.com/show_bug.cgi?id=2542235 issue-tracking
- http://www.openwall.com/lists/oss-security/2026/09/23/5
- https://lists.debian.org/debian-lts-announce/2026/10/msg00050.html