Siemens SCALANCE Improper Authentication (CVE-2020-26139)

medium Tenable OT Security Plugin ID 505332

Synopsis

The remote OT asset is affected by a vulnerability.

Description

An issue was discovered in the kernel in NetBSD 7.1. An Access Point (AP) forwards EAPOL frames to other clients even though the sender has not yet successfully authenticated to the AP. This might be abused in projected Wi-Fi networks to launch denial-of-service attacks against connected clients and makes it easier to exploit other vulnerabilities in connected clients.

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: Medium

ID: 505332

File Name: tenable_ot_siemens_CVE-2020-26139.nasl

Version: 1.1

Type: Remote

Family: Tenable.ot

Published: 4/21/2026

Updated: 4/21/2026

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v3

Risk Factor: Medium

Base Score: 5.3

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

Vulnerability Information

CPE: cpe:/o:siemens:scalance_w1788-1_m12_firmware:3.0.0, cpe:/o:siemens:scalance_w1788-2ia_m12_firmware:3.0.0, cpe:/o:siemens:scalance_w1788-2_m12_firmware:3.0.0, cpe:/o:siemens:scalance_w1748-1_m12_firmware:3.0.0, cpe:/o:siemens:scalance_w1788-2_eec_m12_firmware:3.0.0, cpe:/o:siemens:scalance_w761-1_rj45_firmware:6.6.0, cpe:/o:siemens:scalance_w788-2_m12_eec_firmware:6.6.0, cpe:/o:siemens:scalance_w786-2_rj45_firmware:6.6.0, cpe:/o:siemens:scalance_wam766-1_firmware:1.2.0, cpe:/o:siemens:scalance_w788-1_rj45_firmware:6.6.0, cpe:/o:siemens:scalance_w778-1_m12_eec_%28usa%29_firmware:6.6.0, cpe:/o:siemens:scalance_wum766-1_%28usa%29_firmware:1.2.0, cpe:/o:siemens:scalance_w734-1_rj45_%28usa%29_firmware:6.6.0, cpe:/o:siemens:scalance_wum766-1_firmware:1.2.0, cpe:/o:siemens:scalance_wam766-1_eec_firmware:1.2.0, cpe:/o:siemens:scalance_wum763-1_firmware:1.2.0, cpe:/o:siemens:scalance_w788-2_m12_firmware:6.6.0, cpe:/o:siemens:scalance_w774-1_rj45_firmware:6.6.0, cpe:/o:siemens:scalance_w786-2ia_rj45_firmware:6.6.0, cpe:/o:siemens:scalance_w786-2_sfp_firmware:6.6.0, cpe:/o:siemens:scalance_w786-1_rj45_firmware:6.6.0, cpe:/o:siemens:scalance_w778-1_m12_eec_firmware:6.6.0, cpe:/o:siemens:scalance_w721-1_rj45_firmware:6.6.0, cpe:/o:siemens:scalance_w748-1_rj45_firmware:6.6.0, cpe:/o:siemens:scalance_wam763-1_firmware:1.2.0, cpe:/o:siemens:scalance_w774-1_m12_eec_firmware:6.6.0, cpe:/o:siemens:scalance_w734-1_rj45_firmware:6.6.0, cpe:/o:siemens:scalance_wam766-1_%28us%29_firmware:1.2.0, cpe:/o:siemens:scalance_w774-1_rj45_%28usa%29_firmware:6.6.0, cpe:/o:siemens:scalance_w788-1_m12_firmware:6.6.0, cpe:/o:siemens:scalance_w778-1_m12_firmware:6.6.0, cpe:/o:siemens:scalance_w748-1_m12_firmware:6.6.0, cpe:/o:siemens:scalance_w722-1_rj45_firmware:6.6.0, cpe:/o:siemens:scalance_wam766-1_eec_%28us%29_firmware:1.2.0, cpe:/o:siemens:scalance_w788-2_rj45_firmware:6.6.0, cpe:/o:siemens:scalance_w738-1_m12_firmware:6.6.0

Required KB Items: Tenable.ot/Siemens

Exploit Ease: No known exploits are available

Patch Publication Date: 7/13/2021

Vulnerability Publication Date: 7/13/2021

Reference Information

CVE: CVE-2020-26139

CWE: 287

ICSA: 22-104-04

Detections

Analytics