Hitachi Energy RTU500 Missing Authentication for Critical Function (CVE-2026-8065)

critical Tenable OT Security Plugin ID 506491

Synopsis

The remote OT asset is affected by a vulnerability.

Description

An authentication bypass vulnerability in the firmware update endpoint of Hitachi Energy RTU500 allows an unauthenticated attacker to upload arbitrary firmware through a crafted POST request. Successful exploitation could allow the attacker to modify device functionality or compromise the integrity or availability of the device.

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: 506491

File Name: tenable_ot_abb_CVE-2026-8065.nasl

Version: 1.1

Type: Remote

Family: Tenable.ot

Published: 10/27/2026

Updated: 10/27/2026

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: Medium

Score: 4.3

Percentile: 53.54

CVSS v3

Risk Factor: Critical

Base Score: 9.1

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

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-2026-8065

CWE: 306

ICSA: 26-279-06

Detections

Analytics