CVE-2025-3496 is a high-severity buffer overflow vulnerability classified under CWE-120, affecting the Auma Riester AC1.2 actuator device, specifically version 06.00.00. This vulnerability arises from improper handling of input data sizes during buffer copy operations over the device's Bluetooth or RS-232 interfaces. An unauthenticated remote attacker can exploit this flaw without requiring any privileges or user interaction. By sending specially crafted input data, the attacker can trigger a buffer overflow condition, which may cause unexpected device behavior or lead to a denial-of-service (DoS) state. The vulnerability does not impact confidentiality or integrity directly but severely affects availability by potentially crashing or destabilizing the device. The device's interfaces—Bluetooth and RS-232—are commonly used for remote control and monitoring in industrial environments, making this vulnerability particularly critical in operational technology (OT) contexts. No known exploits are currently reported in the wild, and no patches have been published as of the vulnerability disclosure date (May 12, 2025). The CVSS v3.1 base score is 7.5, reflecting the network attack vector, low attack complexity, no privileges required, no user interaction, and an impact limited to availability disruption.

For European organizations, especially those operating in industrial automation, energy, water management, and infrastructure sectors, this vulnerability poses a significant risk. The Auma Riester AC1.2 actuators are widely used in valve control and other critical industrial processes. Exploitation could lead to operational disruptions, causing downtime, safety hazards, and potential cascading effects on dependent systems. Since the vulnerability can be triggered remotely without authentication, attackers could leverage it to disrupt critical infrastructure or industrial control systems (ICS). The DoS condition could halt essential processes, leading to financial losses and safety incidents. Additionally, the presence of Bluetooth and RS-232 interfaces expands the attack surface, potentially allowing attackers to exploit the vulnerability from nearby physical proximity or through networked serial-to-IP gateways. European organizations with legacy or unpatched Auma Riester devices are particularly vulnerable, as these devices may be embedded in long-lived industrial environments with limited update cycles.

Given the lack of an official patch at the time of disclosure, organizations should implement compensating controls to mitigate risk. First, restrict access to the Bluetooth and RS-232 interfaces by disabling unused communication channels or physically securing access points. Employ network segmentation to isolate devices running Auma Riester AC1.2 actuators from general IT networks and limit exposure to trusted management networks only. Use Bluetooth security features such as pairing restrictions, strong authentication, and encryption to reduce unauthorized access. Monitor network traffic for anomalous or malformed packets targeting these interfaces. Implement strict access control policies and logging for any device management activities. Where possible, replace or upgrade affected devices to versions that address this vulnerability once patches become available. Additionally, conduct regular security assessments of OT environments to identify and remediate similar vulnerabilities proactively.