CVE-2026-54429 in SIMATIC S7-PLCSIM Advanced
Summary
by MITRE • 07/14/2026
A vulnerability has been identified in SIMATIC S7-PLCSIM Advanced (All versions). Affected devices do not properly handle high-volume multicast network traffic, which can exhaust available memory resources in the affected application. This could allow an unauthenticated attacker on the local network segment to cause a denial-of-service condition of the affected application. The affected application becomes inaccessible and requires a manual restart; no project data is lost. Successful exploitation requires a specific project configuration to be already active on the targeted instance.
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Analysis
by VulDB Data Team • 07/14/2026
This vulnerability resides within SIMATIC S7-PLCSIM Advanced software from Siemens, a widely used simulation environment for industrial automation systems. The flaw represents a classic resource exhaustion attack vector that targets memory management within the application's network processing capabilities. When subjected to high-volume multicast traffic, the affected system fails to properly handle or throttle incoming network packets, leading to progressive memory consumption until system resources are completely depleted. This vulnerability specifically impacts devices operating on local network segments where attackers can directly inject malicious multicast traffic without requiring authentication credentials. The attack scenario requires an existing project configuration to be active within the targeted instance, suggesting that merely having the software installed is insufficient for exploitation - the specific industrial control project must already be loaded and running in the simulation environment.
The technical implementation of this vulnerability stems from inadequate input validation and resource management within the network stack processing components of the PLC simulation software. Multicast traffic patterns designed to overwhelm the application's memory allocation mechanisms can cause heap exhaustion or memory leak conditions that prevent normal application operation. The system's failure to implement proper traffic rate limiting or packet filtering mechanisms creates an exploitable condition where malicious actors can systematically consume available memory resources without requiring elevated privileges. This behavior aligns with common denial-of-service attack patterns and corresponds to CWE-400, which addresses unspecified resource exhaustion vulnerabilities in software applications. Network-based attacks of this nature typically fall under ATT&CK technique T1498, specifically targeting network denial-of-service conditions through resource consumption.
The operational impact of successful exploitation manifests as complete application unavailability requiring manual intervention for system recovery. During the attack, the affected PLC simulation instance becomes completely inaccessible to legitimate users and operators, disrupting industrial control system development and testing activities. The requirement for manual restart indicates that automated recovery mechanisms are absent, potentially causing extended downtime in critical development environments or production simulation systems. While project data remains intact and no permanent damage occurs to the underlying system configuration, the service disruption creates significant operational challenges for industrial automation teams relying on continuous simulation capabilities. The local network segment requirement means that attackers must be physically present within the same broadcast domain, limiting but not eliminating the threat surface in connected industrial environments.
Mitigation strategies should focus on network segmentation and access control measures to prevent unauthorized access to the local network segments hosting affected systems. Implementing proper firewall rules and network access controls can restrict multicast traffic flow to authorized sources only, while also blocking unnecessary network access to simulation environments. Network monitoring solutions should be deployed to detect unusual multicast traffic patterns that may indicate attempted exploitation activities. System administrators should ensure that PLC simulation environments are not running in production or critical development scenarios without proper network isolation. Regular security updates from Siemens should be applied promptly when available, and project configurations should only be loaded on systems where necessary for legitimate operational requirements. Additionally, implementing memory monitoring and alerting mechanisms can provide early detection of resource exhaustion conditions before complete system failure occurs, allowing for proactive intervention rather than reactive restart operations.