CVE-2026-2491 identifies a critical authentication bypass vulnerability in the Socomec DIRIS A-40 power monitoring device, specifically affecting firmware version 1.8.1. The vulnerability stems from the device's HTTP API implementation, which listens on TCP port 80 by default and fails to enforce authentication before granting access to critical functions. This lack of authentication (CWE-306) allows an attacker positioned on the same network segment or with network adjacency to bypass security controls and interact with the device's management interface without credentials. The vulnerability does not require any user interaction or prior privileges, making it relatively easy to exploit. The attacker could potentially read sensitive monitoring data, alter device configurations, or disrupt power monitoring operations, impacting the confidentiality, integrity, and availability of the device's functions. Although no public exploits have been reported, the vulnerability was assigned a CVSS v3.0 base score of 6.3, indicating a medium severity level. The issue was reported and published by the Zero Day Initiative (ZDI) under the identifier ZDI-CAN-23993. The absence of authentication on a critical function in an industrial control device poses a significant risk to operational technology environments that rely on accurate and secure power monitoring.

The impact of CVE-2026-2491 on organizations worldwide can be significant, especially for those relying on Socomec DIRIS A-40 devices for power monitoring in industrial, commercial, and critical infrastructure environments. Unauthorized access to the device's management interface could allow attackers to manipulate power monitoring data, potentially leading to incorrect energy usage reporting, financial losses, or masking of malicious activities. Altering device configurations could disrupt power monitoring operations, affecting operational continuity and safety. In critical infrastructure sectors such as energy, manufacturing, and data centers, this could lead to cascading effects on service availability and reliability. The vulnerability's ease of exploitation without authentication or user interaction increases the risk of automated or opportunistic attacks. Although no known exploits are currently active in the wild, the potential for future exploitation exists, especially if attackers develop automated tools. Organizations could face regulatory and compliance risks if compromised devices lead to data integrity issues or operational failures.

To mitigate CVE-2026-2491, organizations should implement the following specific measures: 1) Immediately restrict network access to the Socomec DIRIS A-40 management interface by isolating the device on a dedicated management VLAN or network segment with strict access controls and firewall rules limiting access to trusted administrators only. 2) Monitor network traffic to and from the device for unusual or unauthorized access attempts, particularly on TCP port 80. 3) Engage with Socomec to obtain and apply any available firmware updates or patches addressing this vulnerability as soon as they are released. 4) If firmware updates are not yet available, consider disabling the HTTP API or replacing it with a more secure management interface if supported. 5) Implement network intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics to detect attempts to exploit authentication bypass on the device. 6) Conduct regular security assessments and penetration testing of operational technology environments to identify and remediate similar vulnerabilities. 7) Educate operational technology and IT staff about the risks of unmanaged or poorly secured industrial devices and enforce strict device hardening policies.