CVE-2026-17539: Hitachi Energy RTU500 Series Cmu Firmware

Medium severity, CVSS 5.9. EPSS: 0.3% chance of exploitation in the next 30 days.

RTU500 has a vulnerability, where high-load scenarios, such as sending GI requests at short intervals, may cause a NULL pointer dereference in the last entry of the enhanced message queue. This can cause a BCI_IEC104 fatal write error, resulting in connection interruption and restart, and ultimately a denial of service for bidirectional IEC 60870-5-104 communication.

Affected products

• Hitachi Energy RTU500 Series Cmu Firmware: from 12.7.1, up to and including 12.7.7; from 13.5.1, up to and including 13.5.4; from 13.6.1, up to and including 13.6.3; from 13.7.1, up to and including 13.7.8; from 13.8.1, up to and including 13.8.2

Published 2026-09-03. Last modified 2026-09-03.