---
id: CVE-2026-15579
title: >-
  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
summary: >-
  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 l…
severity: high
cvss: 8.8
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N'
cwe:
  - CWE-787
vendor: Moxa
product: TN-4500B Series
affected:
  - tn-4500b_series >= 1.0 <= 2.0
published: '2026-09-18'
updated: '2026-09-18'
sourceUpdated: '2026-09-18T19:05:01.127'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-15579'
references:
  - url: >-
      https://www.moxa.com/en/support/product-support/security-advisory/mpsa-252620-cve-2026-15579-out-of-bounds-write-vulnerability-in-ethernet-switch
    label: psirt@moxa.com
tags:
  - nvd
  - cve.org
epss: 0.00442
epssPercentile: 0.35747
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-18T10:38:44.190582Z'
cvssSource: cna
ingestedAt: '2026-09-18T10:39:24.457Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.