Remote Denial of Service Vulnerability in Moxa TN-4500B Series

Moxa has released security advisory MPSA-252620 detailing an out-of-bounds write vulnerability, identified as CVE-2026-15579, affecting the TN-4500B Series of industrial Ethernet switches. The vulnerability exists due to improper handling of input within the device's management interface. A remote, unauthenticated attacker can exploit this flaw by sending specially crafted packets to the affected hardware. Successful exploitation results in an immediate denial-of-service (DoS) condition, rendering the network switch unavailable and potentially disrupting critical industrial communication flows. All versions of the TN-4500B series prior to version 2.1 are affected.

Impact

The impact of this vulnerability is significant, as it permits the disruption of industrial network infrastructure from a remote, unauthenticated position. Organizations relying on the TN-4500B series for critical communications or SCADA operations face an increased risk of operational downtime and loss of visibility into the managed network segments if the device enters a crashed state.

Recommendation

Prioritize the immediate patching of all vulnerable Moxa TN-4500B series switches.

• Upgrade all affected units to firmware version 2.1 or later as specified in Moxa Security Advisory MPSA-252620.
• Restrict network access to the switch management interfaces using firewalls or ACLs to prevent unauthenticated remote access to the vulnerable service until patching is complete.