CVE-2025-12056 is an out-of-bounds read vulnerability classified under CWE-125 found in the Shelly Pro 3EM energy monitoring device firmware versions prior to 1.4.4. The vulnerability arises from improper bounds checking when processing certain inputs, allowing an attacker to read memory beyond allocated buffers. This can lead to disclosure of sensitive information stored in adjacent memory regions, potentially including cryptographic keys, configuration data, or user credentials. The vulnerability has a CVSS 4.0 base score of 8.3, indicating high severity, with an attack vector of adjacent network (AV:A), low attack complexity (AC:L), no privileges required (PR:N), and no user interaction (UI:N). The impact is primarily on confidentiality (VA:H), with no impact on integrity or availability. Exploitation does not require authentication or user interaction, but the attacker must be on the same local network segment as the device, limiting remote exploitation. No public exploits or active exploitation have been reported yet. Shelly Pro 3EM devices are commonly used in smart energy management and monitoring, making this vulnerability relevant for organizations relying on these devices for operational data. The vulnerability was reserved on October 22, 2025, and published on November 19, 2025. No official patches or mitigation links are currently provided, but upgrading to firmware version 1.4.4 or later is expected to resolve the issue. The vulnerability's presence in critical energy infrastructure devices underscores the importance of timely remediation and network access controls.

For European organizations, the primary impact of CVE-2025-12056 is the potential unauthorized disclosure of sensitive operational data from Shelly Pro 3EM devices. This could include energy consumption metrics, device configurations, or cryptographic material, which may be leveraged for further attacks or industrial espionage. Confidentiality breaches could undermine trust in energy management systems and expose organizations to regulatory penalties under GDPR if personal or sensitive data is involved. Although the vulnerability does not directly affect device availability or integrity, information leakage could facilitate lateral movement within networks or targeted attacks on critical infrastructure. The requirement for adjacent network access limits remote exploitation but emphasizes the need for strong internal network segmentation and monitoring. European energy providers, manufacturing plants, and smart building operators using Shelly Pro 3EM devices are particularly at risk. The lack of known exploits reduces immediate risk but does not eliminate the threat, especially as proof-of-concept code could emerge. Overall, the vulnerability poses a significant risk to confidentiality and operational security in energy-related environments across Europe.

1. Immediately update Shelly Pro 3EM devices to firmware version 1.4.4 or later once available to patch the out-of-bounds read vulnerability. 2. Restrict network access to Shelly Pro 3EM devices by implementing strict network segmentation, ensuring these devices are isolated from general user networks and exposed only to trusted management systems. 3. Employ network monitoring tools to detect anomalous traffic patterns or unauthorized access attempts on the local network segment where Shelly devices operate. 4. Use strong authentication and encryption for management interfaces to reduce the risk of unauthorized local network access. 5. Conduct regular vulnerability assessments and penetration testing focused on smart energy devices to identify and remediate similar issues proactively. 6. Maintain an inventory of all Shelly Pro 3EM devices deployed within the organization to ensure timely patch management. 7. Collaborate with vendors and subscribe to security advisories to receive prompt updates on patches and threat intelligence related to Shelly products. 8. Consider deploying network access control (NAC) solutions to enforce device authentication and limit network exposure. 9. Educate operational technology (OT) and IT teams about the risks associated with smart energy devices and the importance of applying security best practices.