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Security Advisories

SUMMARY

CVE-2026-10831: Improper Authorization Vulnerability in Serial Device Servers

This security advisory addresses one vulnerability identified in Serial Device Servers.

CVE-2026-10831

Improper Authorization of Break Signal Commands in Devices 

A denial-of-service vulnerability exists in NPort devices because of improper access control on the command port. The command interface does not properly validate whether a sender is associated with a valid data port session before accepting break signal commands. A remote attacker with network access can send crafted requests to disrupt serial communication for an active user session.

Because the issue is assessed as medium severity, users can evaluate their environment and schedule the update in the next maintenance or update cycle.

 

The Identified Vulnerability Type and Potential Impact 

CVE ID Vulnerability Type Impact
CVE-2026-10831

CWE-862: Missing Authorization

CAPEC-212: Functionality Misuse

Vulnerability Scoring Details 

CVE ID
Base Score
Vector
Severity

Unauthenticated

Remote Exploits

CVE-2026-10831 CVSS 4.0: 6.9

AV:N/AC:L/AT:N/PR:N/UI:N/

VC:N/VI:L/VA:L/SC:N/SI:N/SA:L

Medium Yes
AFFECTED PRODUCTS AND SOLUTIONS

Solutions

Moxa has developed appropriate solutions to address these vulnerabilities. The solutions for the affected products are listed in the following table: 

Product Series Affected Versions Solutions

NPort 6000 Series

  • NPort 6100/6200 Series
  • NPort 6400/6600 Series
Firmware v2.3 and earlier Please contact Moxa Technical Support for the security patch (v2.3.9)
CN2600 Series Firmware v4.6 and earlier Please contact Moxa Technical Support for the security patch (v4.6.11)

 

Mitigations

For users who may not be able to perform a firmware update, we provide the following recommended mitigation measures as an alternative to mitigate the risk associated with the vulnerability.

  • Refer to the General Security Recommendations section to further strengthen your security context.

 

General Security Recommendations

To safeguard devices and networks, we recommend implementing the following recommendations to mitigate potential risks:

  1. Restrict Network Access
    • Use firewalls or access control lists (ACLs) to limit communication to trusted IP addresses and networks.
    • Segregate operational networks from other networks (e.g., enterprise networks) using VLANs or physical separation.
  2. Minimize Exposure
    • Avoid exposing devices directly to the Internet.
    • Disable unused network services and ports to reduce the attack surface.
  3. Enhance Device Authentication and Access Control
    • Implement multi-factor authentication (MFA) for accessing critical systems.
    • Use role-based access control (RBAC) to enforce the principle of least privilege.
    • Prohibit the use of weak passwords and enforce a password policy that includes password complexity requirements, periodic password changes, and restrictions on password reuse.
  4. Regularly Update Firmware and Software
    • Keep devices updated with the latest firmware versions and security patches.
    • Establish a regular patch management schedule to address newly identified vulnerabilities.
  5. Secure Remote Access
    • Use encrypted communication protocols (e.g., VPN, SSH) for remote access.
    • Restrict remote access to authorized personnel only and enforce strong authentication mechanisms.
  6. Implement Anomaly Detection Techniques
    • Monitor network traffic and device behavior for unusual or unauthorized activities.
    • Use tools or techniques that can identify anomalies and provide alerts for potential threats.
  7. Implement Logging and Monitoring
    • Enable event logging and maintain audit trails on devices.
    • Regularly review logs for anomalies and unauthorized access attempts.
  8. Conduct Regular Security Assessments
    • Perform vulnerability assessments to identify potential risks.
    • Regularly review device configurations to ensure compliance with security policies.

 

Acknowledgement

We would like to express our gratitude to Artur Witek for reporting the vulnerability, collaborating with us to enhance the security of our products, and contributing to our efforts to deliver better service to our customers.

 

Revision History:

VERSION DESCRIPTION RELEASE DATE
1.0 First release June 16, 2026

Relevant Products

CN2600 Series · NPort 6100/6200 Series · NPort 6400/6600 Series ·

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