CVE-2026-25894: FUXA SCADA RCE Vulnerability

CVE-2026-25894 Overview

CVE-2026-25894 is an insecure default configuration vulnerability in FUXA, a web-based Process Visualization (SCADA/HMI/Dashboard) software. When authentication is enabled but the administrator JWT secret is not properly configured, an unauthenticated remote attacker can gain administrative access and execute arbitrary code on the server. This vulnerability affects FUXA through version 1.2.9 and has been patched in version 1.2.10.

Critical Impact

This vulnerability allows unauthenticated remote attackers to gain full administrative control over FUXA SCADA/HMI systems, potentially enabling arbitrary code execution on critical industrial control infrastructure.

Affected Products

• FUXA versions through 1.2.9
• FUXA installations with authentication enabled but unconfigured JWT secret
• Web-based SCADA/HMI/Dashboard deployments using vulnerable FUXA versions

Discovery Timeline

• 2026-02-09 - CVE-2026-25894 published to NVD
• 2026-02-10 - Last updated in NVD database

Technical Details for CVE-2026-25894

Vulnerability Analysis

This vulnerability stems from CWE-321 (Use of Hard-coded Cryptographic Key), where FUXA fails to enforce a unique JWT secret configuration when authentication is enabled. The insecure default configuration allows attackers to forge valid JWT tokens and authenticate as administrators without proper credentials. Once administrative access is obtained, attackers can leverage the platform's capabilities to execute arbitrary code on the underlying server, posing significant risks to industrial control systems that rely on FUXA for process visualization.

The attack can be performed remotely over the network, though it requires some complexity in token forgery and specific preconditions where authentication is enabled but the JWT secret remains unconfigured. The impact extends beyond the vulnerable component, potentially affecting connected SCADA systems and industrial processes.

Root Cause

The root cause is the use of a predictable or hardcoded cryptographic key for JWT token generation when administrators fail to configure a custom secret. FUXA's authentication mechanism relies on JWT tokens for session management, but when the administrator JWT secret is not explicitly configured, the application falls back to a default value. This allows attackers with knowledge of the default secret to generate valid administrative tokens.

Attack Vector

The attack is network-based and requires no user interaction or prior authentication. An attacker can exploit this vulnerability by:

1. Identifying a FUXA instance with authentication enabled but unconfigured JWT secret
2. Crafting a forged JWT token using the default/predictable secret
3. Presenting the forged token to gain administrative access
4. Leveraging administrative privileges to execute arbitrary code on the server

The vulnerability is particularly concerning for SCADA/HMI environments where FUXA may be deployed to monitor and control industrial processes, as compromised systems could lead to physical safety risks.

Detection Methods for CVE-2026-25894

Indicators of Compromise

• Unexpected administrative sessions or logins from unknown IP addresses
• JWT tokens with suspicious creation timestamps or originating from external sources
• Unauthorized modifications to FUXA project configurations or dashboards
• Evidence of code execution or process spawning from the FUXA application process

Detection Strategies

• Monitor authentication logs for administrative access attempts from unexpected sources
• Implement network traffic analysis to detect anomalous JWT token patterns
• Deploy file integrity monitoring on FUXA configuration and project files
• Review web server logs for suspicious API calls to administrative endpoints

Monitoring Recommendations

• Enable verbose logging for all authentication events in FUXA
• Configure alerting for any administrative configuration changes
• Monitor outbound network connections from the FUXA server for signs of post-exploitation activity
• Implement baseline monitoring for normal SCADA/HMI traffic patterns to detect anomalies

How to Mitigate CVE-2026-25894

Immediate Actions Required

• Upgrade FUXA to version 1.2.10 or later immediately
• Configure a strong, unique JWT secret in the FUXA authentication settings
• Review access logs for any signs of unauthorized administrative access
• Restrict network access to FUXA installations using firewall rules or network segmentation

Patch Information

The vulnerability has been addressed in FUXA version 1.2.10. The fix ensures that JWT secrets must be explicitly configured and prevents the use of default or predictable values. Administrators should upgrade immediately and review their authentication configuration.

For technical details on the fix, see the GitHub Commit and the GitHub Release v1.2.10. Additional information is available in the GitHub Security Advisory GHSA-32cc-x95p-fxcg.

Workarounds

• If immediate upgrade is not possible, configure a strong, random JWT secret manually in the FUXA configuration
• Implement network-level access controls to restrict FUXA access to trusted networks only
• Deploy a web application firewall (WAF) to monitor and filter suspicious authentication requests
• Consider disabling remote access to FUXA until the patch can be applied

# Configuration example - Set a strong JWT secret
# In FUXA configuration file or environment variables:
export JWT_SECRET="$(openssl rand -base64 64)"
# Ensure the secret is at least 256 bits of entropy
# Restart FUXA service after configuration
systemctl restart fuxa