Phoenix Contact AXL F BK and IL BK Bus Couplers Denial-of-Service Vulnerability

A denial-of-service vulnerability has been identified in several Phoenix Contact AXL F BK and IL BK bus couplers. An unauthenticated remote attacker can overload the device by sending a high volume of requests to the HTTP service on port 80. This issue affects multiple product variants and versions, with the bus coupler requiring a manual restart to restore communication within the Industrial Ethernet.

Impact

Exploitation of this vulnerability leads to device overload, triggering the hardware watchdog. As a result, process data reverts to the configured substitute value behavior. The bus coupler must be manually restarted to restore communication, such as by resetting the power supply, pressing the reset button, or executing the SNMP reset command.

Remediation

Users can upgrade to the fixed firmware versions available for the affected products. For AXL F BK PN TPS and AXL F BK PN TPS XC, firmware version 2.00 will be available in Q4 2025. AXL F BK ETH and AXL F BK ETH XC users can upgrade to version 1.32. For products marked as 'discontinued', no fix is planned.