CVE-2020-12521: Phoenixcontact Plcnext Firmware

Medium severity, CVSS 6.5. EPSS: 0.5% chance of exploitation in the next 30 days.

On Phoenix Contact PLCnext Control Devices versions before 2021.0 LTS a specially crafted LLDP packet may lead to a high system load in the PROFINET stack. An attacker can cause failure of system services or a complete reboot.

Affected products

• Phoenixcontact Plcnext Firmware: before 2021.0 (fixed in 2021.0)

Published 2020-12-17. Last modified 2026-06-17.