# Moxa TN-4500B switch flaw allows remote DoS

Published: 2026-09-18 · Severity: routine · Sectors: infrastructure, manufacturing
Canonical: https://vorant.io/reports/8fca243d-7e6f-5a7d-bb34-4e021fa8e21e/moxa-tn-4500b-switch-flaw-allows-remote-dos

> An out-of-bounds write vulnerability in Moxa TN-4500B Series switches before version 2.1 lets attackers trigger remote denial of service.

CERT-FR published an advisory relaying Moxa's security bulletin MPSA-252620 regarding CVE-2026-15579, an out-of-bounds write vulnerability affecting Moxa TN-4500B Series Ethernet switches running firmware versions prior to 2.1. Exploitation of this flaw allows a remote attacker to cause a denial of service condition on the affected device, potentially disrupting network connectivity in industrial or critical infrastructure environments where these switches are commonly deployed.

No evidence of active exploitation in the wild is mentioned in the advisory. Moxa has released a fix; affected organizations should upgrade TN-4500B Series devices to version 2.1 or later as referenced in the vendor's security bulletin. Given Moxa's presence in industrial control system and operational technology networks, defenders in infrastructure and manufacturing sectors should prioritize patching to avoid availability disruptions.

## Mentioned in this report

- Vulnerabilities: CVE-2026-15579

Source reporting: https://www.cert.ssi.gouv.fr/avis/CERTFR-2026-AVI-1205

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