# CISA Advisory: Hitachi Energy RTU500 Vulnerabilities

Published: 2026-10-20 · Severity: elevated · Sectors: Energy
Canonical: https://vorant.io/reports/7a2bdedd-f280-56ca-b884-5feebb21bead/cisa-advisory-hitachi-energy-rtu500-vulnerabilities

> Multiple vulnerabilities in Hitachi Energy RTU500 series CMU firmware could impact confidentiality, integrity and availability; vendor fixes available.

CISA published an ICS advisory detailing multiple vulnerabilities affecting Hitachi Energy RTU500 series CMU firmware, used in energy sector remote terminal units deployed worldwide. The flaws span several weakness classes including NULL pointer dereference, type confusion, use-after-free, cleartext transmission of sensitive information, insufficiently protected credentials, and authentication bypass by capture-replay. Affected firmware versions range across 12.7.1-12.7.7, 13.5.1-13.5.4, 13.6.1-13.6.3, 13.7.1-13.7.8, and 13.8.1-13.8.2.

Hitachi Energy has issued vendor fixes: affected organizations should update to CMU Firmware version 13.9.1, or to interim fixed versions where available (12.7.8, 13.7.9, 13.8.3) depending on their current branch. CISA recommends following general ICS mitigation practices (network segmentation, minimizing exposure of control system devices, use of VPNs for remote access) in addition to applying patches. No public exploitation has been reported; this is a vendor-disclosed advisory requiring patch management action by energy-sector asset owners.

The advisory lists numerous repeated CVE identifiers due to source formatting, but the core set of distinct vulnerability classes affects multiple firmware branches similarly. Defenders operating RTU500 series devices should inventory firmware versions and prioritize patching, particularly given the devices' role in substation automation and SCADA environments within critical energy infrastructure.

## Mentioned in this report

- Vulnerabilities: CVE-2026-11856, CVE-2026-17539, CVE-2026-28388, CVE-2026-6276, CVE-2026-6653, CVE-2026-6732, CVE-2026-8927, CVE-2026-8932, CVE-2026-9079

Source reporting: https://www.cisa.gov/news-events/ics-advisories/icsa-26-293-05

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