CVE-2023-4397: Zyxel Zld

Medium severity, CVSS 4.4. EPSS: 0.2% chance of exploitation in the next 30 days.

A buffer overflow vulnerability in the Zyxel ATP series firmware version 5.37, USG FLEX series firmware version 5.37, USG FLEX 50(W) series firmware version 5.37, and USG20(W)-VPN series firmware version 5.37, could allow an authenticated local attacker with administrator privileges to cause denial-of-service (DoS) conditions by executing the CLI command with crafted strings on an affected device.

Affected products

• Zyxel Zld: version 5.37 only

Published 2023-11-28. Last modified 2026-06-17.