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Hitachi Energy RTU500 Integer Overflow or Wraparound (CVE-2026-25210)

high Tenable OT Security Plugin ID 505377

Synopsis

The remote OT asset is affected by a vulnerability.

Description

In libexpat before 2.7.4, the doContent function does not properly determine the buffer size bufSize because there is no integer overflow check for tag buffer reallocation, primarily causing Denial of Service and potentially confidentiality and integrity impact to the product.

Product is only affected if IEC 61850 functionality 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: High

ID: 505377

File Name: tenable_ot_abb_CVE-2026-25210.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: 6.7

CVSS v3

Risk Factor: High

Base Score: 7.8

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

Vulnerability Information

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

Required KB Items: Tenable.ot/ABB

Patch Publication Date: 5/26/2026

Vulnerability Publication Date: 5/26/2026

Reference Information

CVE: CVE-2026-25210

CWE: 190

ICSA: 26-155-04