In nspawn in systemd 233 through 259 before 260, an escape-to-host action can occur via a crafted optional config file.

An update of the systemd package has been released.

The remote Debian 11 host has packages installed that are affected by multiple vulnerabilities as referenced in the dla-4533 advisory.

    - -------------------------------------------------------------------------     Debian LTS Advisory DLA-4533-1                debian-lts@lists.debian.org     https://www.debian.org/lts/security/                     Arnaud Rebillout     April 15, 2026                                https://wiki.debian.org/LTS
    - -------------------------------------------------------------------------

    Package        : systemd     Version        : 247.3-7+deb11u8     CVE ID         : CVE-2026-4105 CVE-2026-29111 CVE-2026-40225 CVE-2026-40226     Debian Bug     :

    The following vulnerabilities have been discovered systemd:

    CVE-2026-4105

        The systemd-machined service contains an Improper Access Control         vulnerability due to insufficient validation of the class parameter in         the RegisterMachine D-Bus (Desktop Bus) method. A local unprivileged         user can exploit this by attempting to register a machine with a         specific class value, which may leave behind a usable,         attacker-controlled machine object. This allows the attacker to invoke         methods on the privileged object, leading to the execution of         arbitrary commands with root privileges on the host system.

    CVE-2026-29111

        When an unprivileged IPC API call is made with spurious data, a stack         overwrite occurs, with the attacker controlled content.

    CVE-2026-40225

        udev: local root execution can occur via malicious hardware devices         and unsanitized kernel output.

    CVE-2026-40226

        nspawn: an escape-to-host action can occur via a crafted optional         config file.

    For Debian 11 bullseye, these problems have been fixed in version     247.3-7+deb11u8.

    We recommend that you upgrade your systemd packages.

    For the detailed security status of systemd please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/systemd

    Further information about Debian LTS security advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://wiki.debian.org/LTS

Tenable has extracted the preceding description block directly from the Debian security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - In nspawn in systemd 233 through 259 before 260, an escape-to-host action can occur via a crafted optional     config file. (CVE-2026-40226)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Severity
314597	Photon OS 4.0: Systemd PHSA-2026-4.0-1014	Nessus	PhotonOS Local Security Checks	medium
307620	Debian dla-4533 : libnss-myhostname - security update	Nessus	Debian Local Security Checks	medium
307029	Linux Distros Unpatched Vulnerability : CVE-2026-40226	Nessus	Misc.	medium

Detections

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CVE-2026-40226

medium

Tenable Plugins

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medium

medium