Hitachi Energy RTU500

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Summary

Hitachi Energy is publishing this cybersecurity advisory in response to the security findings reported by Dragos affecting end-of-life RTU500 CMU firmware version 9.x. The reported findings are associated with legacy RTU500 firmware versions that were developed according to the cybersecurity requirements, threat landscape, and industry practices that existed at the time of their release. As cybersecurity threats and security expectations have evolved, these end-of-life versions no longer incorporate many of the security controls and hardening measures that are standard in modern industrial control systems. Over successive RTU500 releases, Hitachi Energy has continuously enhanced the security of the product through the introduction of additional security features, protocol hardening, stronger authentication and access controls, encrypted communications, and other security-by-design improvements. While the findings reported by Dragos do not affect currently supported RTU500 CMU firmware versions, there is a likelihood that the end-of-life versions 11.x and prior are affected by these vulnerabilities. Since the end-of-life versions are no longer maintained with security updates, Hitachi Energy strongly recommends upgrading to a currently supported RTU500 firmware version. Customers should also implement appropriate defense-in-depth measures and cybersecurity best practices to reduce risk and strengthen the security posture of their operational environments. Please refer to the Recommended Immediate Actions for information about the mitigation/remediation.

The following versions of Hitachi Energy RTU500 are affected:

• RTU500 series CMU Firmware vers:RTU500_series_CMU_Firmware/<=11.x (CVE-2026-8065, CVE-2026-8066, CVE-2026-8067, CVE-2010-2965, CVE-2014-9195, CVE-2023-46143)

Background

• Critical Infrastructure Sectors: Energy
• Countries/Areas Deployed: Worldwide
• Company Headquarters Location: Switzerland

Vulnerabilities

Acknowledgments

• Dragos reported these vulnerabilities to CISA.

Notice

The information in this document is subject to change without notice and should not be construed as a commitment by Hitachi Energy. Hitachi Energy provides no warranty, express or implied, including warranties of merchantability and fitness for a particular purpose, for the information contained in this document, and assumes no responsibility for any errors that may appear in this document. In no event shall Hitachi Energy or any of its suppliers be liable for direct, indirect, special, incidental or consequential damages of any nature or kind arising from the use of this document, or from the use of any hardware or software described in this document, even if Hitachi Energy or its suppliers have been advised of the possibility of such damages. This document and parts hereof must not be reproduced or copied without written permission from Hitachi Energy and the contents hereof must not be imparted to a third party nor used for any unauthorized purpose. All rights to registrations and trademarks reside with their respective owners.

Support

For additional information and support please contact your product provider or Hitachi Energy service organization. For contact information, see https://www.hitachienergy.com/contact-us/ for Hitachi Energy contact-centers.

General Mitigation Factors

Recommended security practices and firewall configurations can help protect a process control network from attacks that originate from outside the network. Such practices include that process control systems are physically protected from direct access by unauthorized personnel, have no direct connections to the Internet, and are separated from other networks by means of a firewall system that has a minimal number of ports exposed, and others that have to be evaluated case by case. Process control systems should not be used for Internet surfing, instant messaging, or receiving e-mails. Portable computers and removable storage media should be carefully scanned for viruses before they are connected to a control system. Proper password policies and processes should be followed. Additional information on Industrial Control Systems Cybersecurity Best Practices can be found in the Hitachi Energy “Industrial Control Systems Cybersecurity Best Practices” Cybersecurity Notification. [1]

SSVC

SSVCv2/E:N/A:N/2026-09-28T14:38:32Z/

Legal Notice and Terms of Use

This product is provided subject to this Notification (https://www.cisa.gov/notification) and this Privacy & Use policy (https://www.cisa.gov/privacy-policy).

Recommended Practices

CISA recommends users take defensive measures to minimize the exploitation risk of this vulnerability.

Minimize network exposure for all control system devices and/or systems, and ensure they are not accessible from the internet.

Locate control system networks and remote devices behind firewalls and isolate them from business networks.

When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most recent version available. Also recognize VPN is only as secure as its connected devices.

CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.

CISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.

CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets. Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov in the technical information paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.

Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.

Advisory Conversion Disclaimer

This ICSA is a verbatim republication of Hitachi Energy PSIRT 8DBD000251 from a direct conversion of the vendor's Common Security Advisory Framework (CSAF) advisory. This is republished to CISA's website as a means of increasing visibility and is provided "as-is" for informational purposes only. CISA is not responsible for the editorial or technical accuracy of republished advisories and provides no warranties of any kind regarding any information contained within this advisory. Further, CISA does not endorse any commercial product or service. Please contact Hitachi Energy PSIRT directly for any questions regarding this advisory.

Revision History

• Initial Release Date: 2026-09-29

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