CVE-2018-7852 in Modicon M580
Summary
by MITRE
A CWE-248: Uncaught Exception vulnerability exists in all versions of the Modicon M580, Modicon M340, Modicon Quantum, and Modicon Premium which could cause denial of service when an invalid private command parameter is sent to the controller over Modbus.
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Analysis
by VulDB Data Team • 05/29/2026
The vulnerability described in CVE-2018-7852 represents a critical uncaught exception scenario that affects several generations of Schneider Electric Modicon controllers including the M580, M340, Quantum, and Premium series. This flaw resides in the Modbus communication protocol implementation within these industrial control systems, where the controllers fail to properly handle invalid private command parameters that are transmitted through the Modbus interface. The vulnerability is classified under CWE-248, which specifically addresses the scenario where an exception is thrown but not properly caught by the application, leading to unexpected program termination or system instability.
The technical nature of this vulnerability stems from the controllers' inadequate error handling mechanisms when processing Modbus private commands. When an attacker or malfunctioning device sends malformed or invalid parameters to these controllers, the system does not implement proper exception handling routines to gracefully manage such inputs. Instead, the controllers encounter the unexpected data and fail to catch the resulting exception, causing the application to crash or enter an undefined state. This behavior directly impacts the operational integrity of industrial control systems where continuous operation is critical for process automation and safety.
The operational impact of this vulnerability extends beyond simple denial of service, as it can potentially disrupt critical industrial processes that depend on these controllers for proper operation. In manufacturing environments, the Modicon controllers serve as fundamental components in process control systems, and their sudden failure due to unhandled exceptions can lead to production halts, quality control issues, and potential safety hazards. The vulnerability is particularly concerning because it affects multiple controller generations, suggesting a systemic issue in the software architecture rather than an isolated bug. This widespread impact means that organizations with legacy systems across different controller models may face cascading operational disruptions if they have not implemented proper security measures.
The implications of this vulnerability align with several ATT&CK framework techniques including TA0005 (Defense Evasion) and TA0043 (Reconnaissance) as attackers can potentially identify and exploit this weakness to disrupt operations. Organizations implementing these controllers should consider implementing network segmentation to limit access to Modbus ports, deploying intrusion detection systems to monitor for suspicious Modbus traffic patterns, and ensuring that all controllers are running the latest firmware versions that address this specific vulnerability. Additionally, implementing proper input validation at network boundaries and conducting regular security assessments of industrial control systems can help mitigate the risk associated with uncaught exception vulnerabilities in critical infrastructure environments.