Executive brief
Moxa Ethernet switches used in industrial networks contain a buffer overflow vulnerability in their Web login interface. An attacker can send a specially crafted login request with an excessively long username to crash the authentication process, causing the switch to become unavailable and disrupting network operations.
Technical details
An out-of-bounds write vulnerability (CWE-787) exists in Moxa Ethernet switches due to improper validation of the username field length during Web login processing. The vulnerability can be triggered by submitting an overly long username string, which causes a buffer overflow in the authentication handler. An unauthenticated remote attacker can exploit this over the network without requiring any user interaction. The vulnerability results in a crash of the authentication process, causing a Denial of Service (DoS) condition. Moxa has released firmware v2.1 or later to address this issue.
Affected products
- Moxa TN-4500B Series Firmware v2.0 and earlier
Timeline
- 2026-09-18: disclosed
- 2026-09-18: patched: Firmware v2.1 or later available