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Security Advisories

SUMMARY

CVE-2026-15579: Out-of-bounds Write Vulnerability in Ethernet Switch

This security advisory addresses a vulnerability identified in some of the Ethernet switches.

CVE-2026-15579

An out-of-bounds write vulnerability exists in some of the Ethernet switches because of improper validation of the username field length during Web login processing. This may allow a remote attacker to submit a specially crafted overly long input, triggering a buffer overflow that can cause the authentication process to crash and result in a Denial of Service (DoS) attack

Given the high severity of these issues, users should apply the solutions immediately to reduce security risks.

 

The Identified Vulnerability Type and Potential Impact 

CVE ID Vulnerability Type Impact
CVE-2026-15579

CWE-787: Out-of-bounds Write

CAPEC-24: Filter Failure through Buffer Overflow

Vulnerability Scoring Details 

CVE ID
Base Score
Vector
Severity

Unauthenticated

Remote Exploits

CVE-2026-15579

CVSS 4.0: 8.8

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

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

High Yes
AFFECTED PRODUCTS AND SOLUTIONS

Solutions

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

Product Series Affected Versions Solutions
TN-4500B Series Firmware v2.0 and earlier Firmware v2.1 or later

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 Mask Lu 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 September 18, 2026

Relevant Products

TN-4500B Series ·

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