CVE-2026-94422GHSA-2cgv-pwcq-wvpq
xdg-dbus-proxy: message filtering bypass via reply serial allows sandbox escape
Unknown product
CVSS
8.8HighExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.69%Chance of exploitation activity in the next 30 days, higher than 52% of CVEs. Scored 23 Oct 2026FIRST EPSS
What fixes it
A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.
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.
Text from CVE List
Affected versions 2
- Productaffected: all versions before 0.1.9CVE List
- Fedoraaffected: all versions before 0.1.9CVE List
References 6
- github.com/flatpak/xdg-dbus-proxy/commit/e5702fca4dba9600721921fbca2dbc39dc5ca400Fixvia CVE List
- github.com/flatpak/xdg-dbus-proxy/commit/fc027f759316fb2a6c45648200b6f100202eb84eFixvia CVE List
- github.com/flatpak/xdg-dbus-proxy/commit/e4465a0dfe96da3b39929a30a1ac3a22b16223e3Fixvia CVE List
- access.redhat.com/security/cve/CVE-2026-94422Advisoryvia CVE List
- github.com/flatpak/xdg-dbus-proxy/security/advisories/GHSA-2cgv-pwcq-wvpqAdvisoryvia CVE List
- bugzilla.redhat.com/show_bug.cgi?id=2542235Referencevia CVE List