CVE-2026-18273

Executive Summary

CVE-2026-18273 is a local privilege escalation vulnerability in the Kenwood DNR1007XR device caused by incorrect default permissions on a directory associated with the USB filesystem mount point. An attacker who has already achieved low-privileged code execution on the device can exploit this misconfiguration to escalate privileges to root and execute arbitrary code. At the time of this report, no patch is available from any tracked source, and the vulnerability remains unpatched with a CVSS score of 6.6 (medium-high severity).

Technical Analysis

The vulnerability exists within the configuration of the USB filesystem mount point on the Kenwood DNR1007XR device. According to the NVD description, the specific flaw results from incorrect permissions being applied to a directory used by the product. This is classified under CWE-276 (Incorrect Default Permissions), indicating that the product installs or configures system files, directories, or peripherals with overly permissive default access controls.

The attack surface is entirely local and physical. The CVSS vector confirms this: AV:P (Physical) with AC:L (Low Attack Complexity), PR:L (Low Privileges Required), and UI:N (No User Interaction). The attack requires the attacker to physically access the device and have the ability to execute code in an unprivileged context before leveraging this flaw.

The exploitation mechanism is straightforward: because the USB mount directory has overly permissive permissions, a low-privileged process or user can write to or replace content in that directory. On typical Linux-based embedded systems (which the DNR1007XR is presumed to run, given the "USB filesystem mount point" language), mount directories are often owned by root. If permission misconfiguration allows unprivileged writes, an attacker could:

1. Place a malicious executable or library into the misconfigured directory
2. Trigger execution of that code in the context of the mounting process or another privileged process that reads from that directory
3. Achieve arbitrary code execution as root

The NVD description notes that this was tracked as ZDI-CAN-29070 by Trend Micro's Zero Day Initiative, which is a recognized vulnerability research coordination program. The physical attack vector (AV:P) suggests that the attacker requires direct access to the device hardware, though the low attack complexity (AC:L) means no special conditions or race conditions are required.

Insufficient technical detail is available regarding the specific directory path, the exact permission bits that are misconfigured, or the mechanism by which the directory is mounted. These details would typically appear in a vendor advisory or the original ZDI report but are not present in the provided data.

Exploitation Scenarios

Based strictly on the NVD description and the vulnerability class (CWE-276), the following attack chain applies:

Step 1 — Reconnaissance and Initial Access: The attacker must first obtain the ability to execute low-privileged code on the target Kenwood DNR1007XR device. This could be achieved through a separate vulnerability in the device's firmware, applications, or services, or by exploiting a default or weak credential to gain shell access. Because the attack vector is physical (AV:P), the attacker likely requires hands-on access to the device.

Step 2 — Flaw Trigger: Once the attacker has low-privileged code execution, they enumerate the filesystem to identify directories with incorrect default permissions — specifically, the mount point directory for the USB filesystem. The attacker verifies write access to this directory, which should normally be restricted to root or the mounting user.

Step 3 — Payload Deployment and Execution: At the vulnerability-class level, the attacker places a malicious payload (e.g., an executable binary or a shared library) into the misconfigured directory. The payload is designed to execute when a privileged process accesses or reads from that directory. The attacker then triggers the payload's execution — for example, by causing the mount process to re-read its configuration, by waiting for the device to remount the USB filesystem, or by placing a file that is executed by a cron job or startup script.

Step 4 — Privilege Escalation and Post-Exploitation: Successful exploitation results in arbitrary code execution in the context of the root user (or equivalent highest-privilege user on the device). The CVSS vector indicates high impact on confidentiality, integrity, and availability (C:H/I:H/A:H). Post-exploitation, the attacker can modify device firmware, intercept or redirect communications, install persistent backdoors, or render the device inoperable.

No public proof-of-concept (PoC) is available for this vulnerability; the attack chain described above is inferred from the vulnerability class and the CVSS vector.

Impact Assessment

Business Impact: The Kenwood DNR1007XR is a marine navigation and entertainment device commonly installed on boats and vessels. A successful exploit grants the attacker root-level access, enabling full control over the device. Given the device's typical deployment context (marine vessels), the impact extends beyond data compromise to potential operational safety concerns.

Affected Systems: The vulnerability affects the Kenwood DNR1007XR head unit. No specific firmware version range has been confirmed by the vendor, and no patch is currently available.

Blast Radius: The CVSS score of 6.6 with High confidentiality, integrity, and availability impact reflects that this is a significant vulnerability for the affected device. However, the physical attack vector limits the attack surface — an attacker must have physical access to the device. This significantly reduces the potential for remote, large-scale exploitation. The primary concern is for organizations with fleets of vessels using this device, where maintenance technicians or other personnel with physical access could be insiders or could be coerced into facilitating an attack.

CISA KEV: This vulnerability is NOT listed on the CISA Known Exploited Vulnerabilities catalog, and there is no evidence of exploitation in the wild.

Detection Guidance

Generic detection rules are provided below. Because this is a local privilege escalation vulnerability with no specific exploit code or known IoCs, detection focuses on anomalous file system permission changes, unexpected root-level processes, and abnormal access to the USB mount point directory.

Sigma Rule

title: Potential Kenwood DNR1007XR USB Mount Directory Permission Abuse
id: c6e3b7a1-9c42-4f8b-8a32-2b65d192ab01
status: experimental
description: Detects attempts to modify files in the USB mount point directory or changes to directory permissions on Kenwood DNR1007XR devices
author: Valtersit Threat Intelligence
date: 2026/01/15
logsource:
    category: process_creation
    product: linux
detection:
    selection_mount_write:
        Image|endswith:
            - '/cp'
            - '/mv'
            - '/chmod'
            - '/chown'
        CommandLine|contains:
            - '/mnt/usb'
            - '/usb'
            - 'mountpoint'
    selection_permission_change:
        Image|endswith: '/chmod'
        CommandLine|contains: '777'
    condition: selection_mount_write or selection_permission_change
    level: high
falsepositives:
    - Legitimate administrative maintenance of USB storage directories
tags:
    - attack.privilege_escalation
    - attack.t1068
    - cve.2026.18273

YARA Rule

rule CVE_2026_18273_Kenwood_USB_Permission_Abuse
{
    meta:
        author = "Valtersit Threat Intelligence"
        date = "2026-01-15"
        description = "Detects scripts or binaries that modify permissions on USB mount directories, potential CVE-2026-18273 exploitation"
        cve = "CVE-2026-18273"
        reference = "ZDI-CAN-29070"
        score = 60
    strings:
        $permission_cmd = "chmod 777" ascii nocase
        $mount_path = "/mnt/usb" ascii nocase
        $usb_path = "/usb/" ascii nocase
        $mount_cmd = "mount" ascii nocase
        $write_flag = "-o" ascii
        $root_shell = "/bin/sh" ascii
        $chown_cmd = "chown" ascii nocase
    condition:
        any of them and 2 of ($permission_cmd, $mount_path, $usb_path, $chown_cmd)
}

Suricata IDS Rule

alert tcp any any -> any any (msg:"CVE-2026-18273 Kenwood DNR1007XR USB Mount Permission Exploitation Attempt"; flow:established,to_server; content:"chmod"; nocase; content:"777"; distance:0; content:"usb"; nocase; within:40; classtype:attempted-admin; sid:202618273; rev:1; metadata:created_at 2026_01_15, updated_at 2026_01_15, cve CVE-2026-18273, attack_tactic TA0004, attack_technique T1068;)

Note: Because CVE-2026-18273 is a local vulnerability, network-based detection is of limited value. This rule captures traffic that may indicate remote management consoles (e.g., SSH or web administrative interfaces) being used to issue the chmod/mount commands. If no remote management capability exists on the device, network detection will not be effective.

Elastic Detection

process where event.action == "exec" and
  (process.name == "chmod" or process.name == "chown" or process.name == "cp")
  and process.args == "777"
  and (process.args == "/mnt/usb" or process.args like "*usb*")

Splunk SPL Query

(index=linux OR index=syslog) sourcetype=linux_audit
| search (process_name="chmod" OR process_name="chown" OR process_name="cp")
| search (command LIKE "%777%" AND (command LIKE "%usb%" OR command LIKE "%mount%"))
| table _time, host, user, process_name, command
| sort -_time

Wazuh OSSEC Rule

<group name="local,privilege_escalation,">
  <rule id="100273" level="12">
    <if_sid>516</if_sid>
    <match>chmod|chown</match>
    <regex>777</regex>
    <regex>usb</regex>
    <description>CVE-2026-18273: Potential USB mount directory permission escalation on Kenwood DNR1007XR</description>
    <group>privilege_escalation,</group>
    <mitre>
      <id>T1068</id>
    </mitre>
  </rule>
</group>

Mitigation & Patch Guidance

Patch Confidence: 0/4 — UNPATCHED. No patch evidence from any tracked source. The vendor has not released a fix for this vulnerability, and no workarounds are available from official channels.

Immediate Mitigations:

1. Restrict physical access to the Kenwood DNR1007XR device. Because the attack vector is physical (AV:P), limiting physical access to the device is the most effective immediate control. Install the device in a locked or supervised location on the vessel.
2. Audit existing device configurations. Check the permissions on the USB mount point directory and manually correct them to be restrictive (e.g., owned by root with read/execute-only for other users).
3. Disable USB functionality if it is not required for the vessel's operations.
4. Restrict low-privileged code execution paths. Review any services or applications running on the device for other vulnerabilities that could give an attacker the prerequisite low-privileged execution capability.

Patch/Upgrade Steps:

1. Monitor the Kenwood product security advisory pages and the ZDI advisory portal (ZDI-CAN-29070) for firmware updates.
2. When a firmware patch is released, apply it to all affected DNR1007XR units in the fleet immediately.
3. If no patch becomes available within a reasonable timeframe, consider replacing the device with a supported alternative or isolating it from sensitive networks.

Long-Term Hardening:

1. Implement a rigorous physical security program for marine electronics, including controlled access to the helm and equipment areas.
2. Establish an inventory of all Kenwood devices in use, with their firmware versions, to facilitate rapid patch deployment when available.
3. Monitor the ZDI advisory and CVE feeds for updates on CVE-2026-18273 and related findings.
4. Consider a security review of all connected marine electronics to identify similar permission misconfigurations in other devices.

References

1. NVD Entry for CVE-2026-18273 — https://nvd.nist.gov/vuln/detail/CVE-2026-18273
2. ZDI Advisory ZDI-CAN-29070 (referenced in NVD description — monitor ZDI portal for publication) — https://www.zerodayinitiative.com/advisories/
3. Kenwood Product Page for DNR1007XR (for device specifications and firmware update availability) — https://www.kenwood.com (verify product page)
4. CISA Known Exploited Vulnerabilities Catalog — https://www.cisa.gov/known-exploited-vulnerabilities-catalog — CVE-2026-18273 is NOT listed (confirms no known exploitation in the wild)

Threat Actor Activity: No known threat actor campaigns or exploitation-in-the-wild evidence is associated with this vulnerability. It is not listed on CISA KEV. The vulnerability was discovered and coordinated through the ZDI program, indicating responsible disclosure was initiated, but no vendor patch has been observed to date.