CVE-2026-84235 in 1756-ENBT Module
Summary
by MITRE • 09/01/2026
A denial-of-service security issue exists in the affected product. The security issue stems from a crafted CIP packet being sent crashing the module. The device requires a restart to recover.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 09/01/2026
The identified vulnerability represents a critical Denial of Service (DoS) condition within the targeted industrial control system component, specifically triggered by malformed input data transmitted via the Common Industrial Protocol. This protocol is widely utilized in automation environments for real-time communication between programmable logic controllers and other networked devices. The root cause lies in insufficient validation or bounds checking when processing incoming CIP packets. An attacker who can reach the affected module over the network can construct a specially crafted packet that exploits this parsing flaw, leading to an immediate crash of the device's operating system or application layer service. This type of vulnerability is classically categorized under CWE-20 Improper Input Validation and often maps to ATT&CK technique T1499 Endpoint Denial of Service, as it disrupts availability without necessarily compromising confidentiality or integrity initially.
The operational impact of this flaw is severe in industrial settings where continuous uptime is paramount. Because the device requires a manual restart to recover from the crash, any successful exploitation results in an immediate halt of production processes controlled by that module. In critical infrastructure scenarios such as water treatment plants, power grids, or manufacturing lines, even brief interruptions can lead to significant financial losses, safety hazards, or environmental damage. The necessity for physical or remote administrative intervention to restore service further exacerbates the risk, as it introduces a window of vulnerability during which the system is non-functional and potentially susceptible to other attacks if recovery procedures are not strictly monitored.
Mitigation strategies must focus on both immediate containment and long-term remediation. Network segmentation should be implemented to restrict access to CIP-enabled devices only from trusted management stations or specific control networks, thereby reducing the attack surface available to potential adversaries. Additionally, deploying industrial intrusion detection systems capable of inspecting CIP traffic for anomalous packet structures can help identify and block malicious payloads before they reach the vulnerable module. It is imperative that vendors release a firmware update addressing the input validation logic within the protocol stack. Until such patches are applied, administrators should enforce strict access control lists on network switches to limit connectivity to only necessary IP addresses and monitor system logs for signs of repeated connection attempts or unexpected reboots indicative of exploitation activity.