ABB RTU500 Incomplete List of Disallowed Inputs (CVE-2026-1773)

high Tenable OT Security Plugin ID 505207

Synopsis

The remote OT asset is affected by a vulnerability.

Description

IEC 60870-5-104: Potential Denial of Service impact on reception of invalid U-format frame. Product is only affected if IEC 60870-5-104 bi-directional functionality is configured. Enabling secure communication following IEC 62351-3 does not remediate the vulnerability but mitigates the risk of exploitation.

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

Solution

Refer to the vendor advisory.

Plugin Details

Severity: High

ID: 505207

File Name: tenable_ot_abb_CVE-2026-1773.nasl

Version: 1.1

Type: remote

Family: Tenable.ot

Published: 3/4/2026

Updated: 3/4/2026

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v3

Risk Factor: High

Base Score: 7.5

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

Vulnerability Information

CPE: cpe:/o:hitachienergy:rtu530_firmware:13, cpe:/o:hitachienergy:rtu520_firmware:12, cpe:/o:hitachienergy:rtu540_firmware:13, cpe:/o:hitachienergy:rtu520_firmware:13.8.1, cpe:/o:hitachienergy:rtu560_firmware:13, cpe:/o:hitachienergy:rtu530_firmware:12, cpe:/o:hitachienergy:rtu520_firmware:13, cpe:/o:hitachienergy:rtu540_firmware:12, cpe:/o:hitachienergy:rtu560_firmware:12, cpe:/o:hitachienergy:rtu530_firmware:13.8.1, cpe:/o:hitachienergy:rtu540_firmware:13.8.1, cpe:/o:hitachienergy:rtu560_firmware:13.8.1

Required KB Items: Tenable.ot/ABB

Patch Publication Date: 2/24/2026

Vulnerability Publication Date: 2/24/2026

Reference Information

CVE: CVE-2026-1773

CWE: 184

Detections

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