Hitachi Energy RTU500 Relative Path Traversal (CVE-2026-8066)

critical Tenable OT Security Plugin ID 506490

Synopsis

The remote OT asset is affected by a vulnerability.

Description

A directory traversal vulnerability in the file upload functionality of Hitachi Energy RTU500 allows an unauthenticated attacker to write or overwrite arbitrary files on the device file system. Depending on the files affected, successful exploitation could result in unauthorized modification of device data or disruption of the device's intended operation.

According to Hitachi Energy, RTU500 series CMU firmware versions 11.x and prior are affected. All affected versions are End-of-Life.

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 supported version (12.7.8, 13.9.1 or later) as recommended in the Hitachi Energy advisory, and apply the general mitigation factors described in the advisory.

Plugin Details

Severity: Critical

ID: 506490

File Name: tenable_ot_abb_CVE-2026-8066.nasl

Version: 1.2

Type: Remote

Family: Tenable.ot

Published: 10/27/2026

Updated: 10/28/2026

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: High

Score: 7

Percentile: 97.98

CVSS v2

Risk Factor: High

Base Score: 9.4

Temporal Score: 7

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:C/A:C

CVSS Score Source: CVE-2026-8066

CVSS v3

Risk Factor: Critical

Base Score: 9.1

Temporal Score: 7.9

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

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/o:hitachienergy:rtu500_firmware

Required KB Items: Tenable.ot/ABB

Exploit Ease: No known exploits are available

Patch Publication Date: 9/29/2026

Vulnerability Publication Date: 9/29/2026

Reference Information

CVE: CVE-2026-8066

CWE: 23

ICSA: 26-279-06

Detections

Analytics