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Hitachi Energy RTU500 NULL Pointer Dereference (CVE-2026-8479)

medium Tenable OT Security Plugin ID 505378

Synopsis

The remote OT asset is affected by a vulnerability.

Description

IEC 60870-5-104 used in bidirectional mode is vulnerable to a NULL pointer dereference; if a specially crafted sequence of messages is sent for a certain time, this causes Denial of Service impact.

Product is only affected if IEC 60870-5-104 functionality in bidirectional mode (BCI) is configured.

This plugin only works with Tenable.ot.
Please visit https://www.tenable.com/products/tenable-ot for more information.

Solution

Upgrade the RTU500 series CMU firmware to a fixed version (13.8.2, or 13.7.9 / 12.7.8 depending on the installed branch as listed in the Hitachi Energy advisory) and apply the general mitigation factors and workarounds described in the advisory.

See Also

http://www.nessus.org/u?d21730e8

https://www.cisa.gov/news-events/ics-advisories/icsa-26-155-04

Plugin Details

Severity: Medium

ID: 505378

File Name: tenable_ot_abb_CVE-2026-8479.nasl

Version: 1.1

Type: Remote

Family: Tenable.ot

Published: 6/17/2026

Updated: 6/17/2026

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v3

Risk Factor: Medium

Base Score: 6.5

Vector: CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v4

Risk Factor: Medium

Base Score: 6.9

Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Vulnerability Information

CPE: cpe:/o:hitachienergy:rtu560_firmware:12.7, cpe:/o:hitachienergy:rtu520_firmware:12.7, cpe:/o:hitachienergy:rtu540_firmware:12.7, cpe:/o:hitachienergy:rtu530_firmware:12.7, cpe:/o:hitachienergy:rtu540_firmware:13.5, cpe:/o:hitachienergy:rtu530_firmware:13.5, cpe:/o:hitachienergy:rtu560_firmware:13.5, cpe:/o:hitachienergy:rtu520_firmware:13.5, cpe:/o:hitachienergy:rtu520_firmware:13.8.1, cpe:/o:hitachienergy:rtu560_firmware:13.8.1, cpe:/o:hitachienergy:rtu540_firmware:13.8.1, cpe:/o:hitachienergy:rtu530_firmware:13.8.1, cpe:/o:hitachienergy:rtu560_firmware:13.6, cpe:/o:hitachienergy:rtu520_firmware:13.6, cpe:/o:hitachienergy:rtu540_firmware:13.6, cpe:/o:hitachienergy:rtu530_firmware:13.6, cpe:/o:hitachienergy:rtu560_firmware:13.7, cpe:/o:hitachienergy:rtu540_firmware:13.7, cpe:/o:hitachienergy:rtu530_firmware:13.7, cpe:/o:hitachienergy:rtu520_firmware:13.7

Required KB Items: Tenable.ot/ABB

Patch Publication Date: 5/26/2026

Vulnerability Publication Date: 5/26/2026

Reference Information

CVE: CVE-2026-8479

CWE: 476

ICSA: 26-155-04