What’s Vulnerable › Vulnerabilities

CVE-2026-94422: xdg-dbus-proxy: message filtering bypass via reply serial allows sandbox escape

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-02 · updated 2026-10-24
• Weakness: CWE-290

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 products

• Fedora: before 0.1.9 — fixed in 0.1.9
• Red Hat Enterprise Linux 10: all versions
• Red Hat Enterprise Linux 9: all versions

How to fix

Upgrade to a fixed version: Fedora 0.1.9. Check the vendor advisory for mitigations.

References

• https://access.redhat.com/security/cve/CVE-2026-94422
• https://bugzilla.redhat.com/show_bug.cgi?id=2542235
• https://github.com/flatpak/xdg-dbus-proxy/commit/e4465a0dfe96da3b39929a30a1ac3a22b16223e3
• https://github.com/flatpak/xdg-dbus-proxy/commit/e5702fca4dba9600721921fbca2dbc39dc5ca400
• https://github.com/flatpak/xdg-dbus-proxy/commit/fc027f759316fb2a6c45648200b6f100202eb84e
• https://github.com/flatpak/xdg-dbus-proxy/security/advisories/GHSA-2cgv-pwcq-wvpq
• http://www.openwall.com/lists/oss-security/2026/09/23/5
• https://lists.debian.org/debian-lts-announce/2026/10/msg00050.html

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