CVE-2026-25894 is a critical security vulnerability affecting frangoteam's FUXA software, a web-based platform used for process visualization in SCADA, HMI, and dashboard applications. The root cause is the use of a hard-coded cryptographic key for the administrator JWT secret when authentication is enabled but the secret is left at its default or unconfigured state. This insecure default configuration violates secure cryptographic practices (CWE-321) and leads to a scenario where an unauthenticated remote attacker can bypass authentication controls. By exploiting this vulnerability, the attacker can gain full administrative privileges and execute arbitrary code on the server hosting FUXA. This can lead to complete compromise of the affected system, including unauthorized control over industrial processes visualized by FUXA. The vulnerability affects all versions prior to 1.2.10, where the issue has been patched by requiring proper configuration of the JWT secret. The CVSS 4.0 vector indicates network attack vector (AV:N), high attack complexity (AC:H), no privileges required (PR:N), no user interaction (UI:N), and high impact on confidentiality, integrity, and availability (C:H, I:H, A:H). Although no exploits are currently known in the wild, the critical nature of the flaw and its potential for remote code execution make it a high priority for remediation. The vulnerability also relates to CWE-1188, which concerns insecure default configurations that can lead to security issues.

The impact on European organizations using FUXA is significant due to the critical nature of the vulnerability. Successful exploitation allows attackers to gain administrative access without authentication, enabling full control over the FUXA server. This can lead to unauthorized manipulation of industrial control processes, data theft, disruption of operations, and potential safety hazards in environments relying on SCADA/HMI systems. The confidentiality of sensitive operational data is compromised, integrity of process visualization and control commands can be altered, and availability of the system may be disrupted by arbitrary code execution. Given the widespread use of SCADA and HMI systems in European manufacturing, energy, and critical infrastructure sectors, this vulnerability poses a substantial risk to operational continuity and safety. The ease of remote exploitation without user interaction further increases the threat level. Organizations failing to patch or properly configure the JWT secret expose themselves to potential targeted attacks or automated exploitation once public exploit code becomes available.

To mitigate this vulnerability, European organizations should immediately upgrade FUXA installations to version 1.2.10 or later, where the insecure default configuration has been corrected. It is critical to verify that the administrator JWT secret is explicitly configured with a strong, unique cryptographic key rather than relying on any default or hard-coded values. Network segmentation should be employed to restrict access to FUXA servers, limiting exposure to untrusted networks. Monitoring and logging of administrative access attempts should be enhanced to detect any unauthorized activities. Organizations should conduct audits of their SCADA/HMI environments to identify any instances of vulnerable FUXA versions and remediate them promptly. Additionally, implementing multi-factor authentication for administrative access where possible can add a layer of defense. Regular vulnerability scanning and penetration testing focused on SCADA components can help detect similar misconfigurations. Finally, maintaining an incident response plan tailored to industrial control system compromises will improve readiness in case of exploitation.