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2023-06-25 08:00 (CEST)

Last update

2023-06-23 07:03 (CEST)


WAGO GmbH & Co. KG


An unauthenticated attacker with network access to port 502/TCP of the target device can cause a denial-of-service condition by sending multiple specially crafted packets. The MODBUS server does not properly release memory resources that were reserved for incomplete connection attempts by MODBUS clients. This could allow a remote attacker to generate a denial of service condition on devices that incorporate a vulnerable version of the MODBUS server.

Last Update:

14. Juni 2023 16:44


Uncontrolled Resource Consumption  (CWE-400) 


Uncontrolled resource consumption in Series WAGO 750-3x/-8x products may allow an unauthenticated remote attacker to DoS the MODBUS server with specially crafted packets.


Abusing this vulnerability an attacker can crash an affected product, which fully prevents the product to work as intended. After a complete restart the component works as expected.



In case no MODBUS communication is needed the MODBUS-Server should be deactivated in the product settings of the web-based management.

As general security measures WAGO strongly recommends:

  1. Use general security best practices to protect systems from local and network attacks.
  2. Do not allow direct access to the device from untrusted networks.
  3. Update to the latest firmware according to the table in chapter solutions.
  4. Industrial control systems (ICS) should not be directly accessible from the Internet, but should be protected by consistently applying the defense-in-depth strategy. The BSI provides general information on securing ICS in the ICS Compendium (


We recommend all effected users to update to the firmware version listed below:

Series WAGO 750-3x/-8x
Article Number Fixed in Firmware Version
750-332 FW11 after BACnet certification
750-362/xxx-xxx FW11 Q3/2023
750-363/xxx-xxx FW11 Q3/2023
750-364/xxx-xxx FW11 Q3/2023
750-365/xxx-xxx FW11 Q3/2023
750-823 FW11 Q3/2023
750-832/xxx-xxx FW11 after BACnet certification
750-862 FW11 Q1/2023
750-890/xxx-xxx FW11 Q3/2023
750-891 FW11 Q3/2023
750-893 FW11 Q3/2023

Reported by

WAGO thanks Roman Ezhov from Kaspersky for reporting.

CERT@VDE coordinated with WAGO.