CVE-2026-25893 identifies a critical improper authorization vulnerability (CWE-285) in frangoteam's FUXA software, a web-based process visualization tool commonly used in SCADA, HMI, and dashboard applications. The flaw exists in versions prior to 1.2.10 and allows unauthenticated remote attackers to bypass authentication controls via the heartbeat refresh API endpoint. This API, intended for routine status updates, fails to enforce proper authorization checks, enabling attackers to gain administrative privileges without any credentials. Once administrative access is obtained, the attacker can execute arbitrary code on the server hosting FUXA, potentially leading to full system compromise. The vulnerability is rated with a CVSS 4.0 score of 10.0, indicating critical severity due to network attack vector, no required privileges or user interaction, and high impact on confidentiality, integrity, and availability. The vulnerability affects all deployments running vulnerable versions, particularly those integrated into industrial control systems and critical infrastructure monitoring. Although no public exploits have been reported yet, the ease of exploitation and potential impact make this a high-risk vulnerability. The vendor has addressed the issue in FUXA version 1.2.10, which enforces proper authorization on the heartbeat refresh API and prevents unauthorized administrative access and code execution.

The impact on European organizations using vulnerable FUXA versions is substantial. Given FUXA's role in SCADA and HMI environments, exploitation could lead to unauthorized control over industrial processes, data manipulation, and disruption of critical infrastructure operations. Confidentiality breaches could expose sensitive operational data, while integrity violations may cause incorrect process visualization or control commands, potentially leading to physical damage or safety hazards. Availability could also be compromised if attackers disrupt or disable the FUXA service. European sectors such as manufacturing, energy, water treatment, and transportation that rely on process visualization tools are at heightened risk. The ability to execute arbitrary code remotely without authentication significantly raises the threat level, enabling attackers to deploy malware, ransomware, or conduct espionage. The lack of known exploits in the wild currently provides a window for mitigation, but the critical nature demands immediate attention to prevent potential attacks.

European organizations should promptly upgrade all FUXA deployments to version 1.2.10 or later, where the vulnerability is patched. Until upgrades can be completed, organizations should restrict network access to the heartbeat refresh API endpoint using firewall rules or network segmentation to limit exposure to untrusted networks. Implement strict monitoring and logging of API access to detect anomalous or unauthorized requests. Employ intrusion detection systems (IDS) tailored to recognize exploitation attempts targeting FUXA. Conduct thorough audits of existing FUXA installations to identify vulnerable versions and remove or isolate outdated instances. Additionally, enforce strong network-level access controls around SCADA and HMI systems, including VPNs and zero-trust principles, to reduce attack surface. Regularly update and test incident response plans specific to industrial control system compromises. Collaboration with vendors and sharing threat intelligence within European cybersecurity communities can enhance preparedness and response.