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ABB/EL/ELSB/Building Automation File integrity can be bypassed in KNX Update Tool for classic KNX products

MEDIUM
CVSS 6.4
Date 2026-07-17T00:30:00+00:00
Source abb-psirt
Published by ABB PSIRT

// Description

ABB has been contacted by a researcher who identified a vulnerability in one of its products. ABB has been contacted by a researcher who identified a vulnerability in one of its products. The vulnerability report has been shared in responsible disclosure. An attacker who successfully exploited this vulnerability could cause the product to become unusable. ABB confirms the vulnerability but at the same time acknowledges that the issue affects exclusively classic KNX devices that are not supporting the latest KNX Secure standard. Due to a lack of security in legacy KNX devices, the issue cannot be resolved via a software change. In order to actively exploit this vulnerability, an attacker requires physical access to the bus, the affected device is connected to. ABB has no plans of corrective measures.

// Vulnerabilities (1)

CVE ID CVSS Score Severity Description
CVE-2026-12705 6.4 medium
CVE-2026-12705. There is no protection of the integrity of the firmware image. This applies exclusively to legacy KNX products

// Remediations (1)

Mitigation: Due to the nature of the classic KNX protocol stack and security concept, there are no options to re
Due to the nature of the classic KNX protocol stack and security concept, there are no options to resolve the vulnerability with a software update on a technical level. ABB recommends to follow general security recommendations listed in the security guideline (see References and General security recommendations). In addition, it shall be avoided to control sensitive functionality by legacy KNX devices such as, but not limited to, access control to e.g. hotel rooms or other protected areas. Note: Legacy KNX standards were never designed to meet state of the art security standards like introduced with KNX Data Secure published in 2017.

// References