A critical privilege escalation vulnerability in WAGO PFC200 G2 firmware allows attackers to elevate to administrative privileges by manipulating session cookie parameters.

The firmware fails to validate or verify the integrity of user session cookies (CWE-565). By modifying the 'name' and 'roles' parameters within the cookie, a low-privileged user can gain administrative access to the device.

This vulnerability allows an attacker to bypass authentication and gain full administrative control over the PLC. This could lead to unauthorized modification of industrial processes, disruption of critical infrastructure, or full device compromise, resulting in significant operational and safety impacts.

Immediate Action: Contact WAGO support to obtain the latest firmware update that addresses this session integrity issue.

Proactive Monitoring: Monitor device traffic for anomalous HTTP requests involving session cookie modification and audit administrative logs for unauthorized account changes.

Compensating Controls: Use network segmentation to ensure the PLC management interface is not exposed to untrusted networks and utilize VPNs or jump servers to restrict access to authorized personnel only.

Public Exploit Available: Yes — an entry exists on ExploitDB.

Due to the availability of a public exploit and the critical nature of the impact, users of the WAGO 750-8212 PFC200 G2 should immediately restrict management access to the device and coordinate with WAGO to apply the necessary firmware remediation.