# Hitachi Energy Relion/SAM600-IO DoS via unthrottled resources

Published: 2025-09-02 · Severity: routine · Sectors: energy, infrastructure
Canonical: https://vorant.io/reports/4bbce60f-e3c9-5f48-8fa1-79e51aace705/hitachi-energy-relion-sam600-io-dos-via-unthrottled-resources

> Remote denial-of-service in Hitachi energy devices via unthrottled resource allocation; no active exploitation reported.

Hitachi Energy has disclosed a denial-of-service vulnerability in Relion 670/650 and SAM600-IO series devices affecting multiple firmware versions. The flaw stems from improper prioritization of network traffic over protection mechanisms (CWE-770), allowing unauthenticated remote attackers with low complexity to exhaust device resources and disrupt critical functions such as the Line Distance Communication Module (LDCM). The vulnerability receives CVSS v4 score of 8.7 and v3.1 score of 7.5, reflecting remote exploitability with no authentication or user interaction required.

Affected versions span Relion 650 (2.2.4.4 through 2.2.6.2), Relion 670 (2.2.2.6 through 2.2.6.2), and SAM600-IO (2.2.5.6). Hitachi has released patches: version 2.2.6.3 for Relion series 2.2.6.x, version 2.2.5.7 for 2.2.5.x series, and version 2.2.4.5 for 2.2.4.x series. Organizations should prioritize updating to the latest available versions and apply standard ICS hardening: network isolation, firewall segmentation, and VPN access controls. CISA has not observed exploitation in the wild at time of publication.

## Mentioned in this report

- Vulnerabilities: CVE-2025-2403

Source reporting: https://www.cisa.gov/news-events/ics-advisories/icsa-25-182-06

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