ABB Busch-Welcome 2 Wire Door Opener Actuator
View CSAF
Summary
ABB is aware of vulnerabilities in the product versions listed as affected in the advisory. An attacker who successfully exploited this vulnerability could gain physical, unauthorized access to a Building where the product is installed
The following versions of ABB Busch-Welcome 2 Wire Door Opener Actuator are affected:
Switch Actuator 4 DU vers:all/*˙
Switch actuator, door/light 4 DU vers:all/*˙
CVSS
Vendor
Equipment
Vulnerabilities
v3 6.8
ABB
ABB Busch-Welcome 2 Wire Door Opener Actuator
Active Debug Code
Background
Critical Infrastructure Sectors: Commercial Facilities
Countries/Areas Deployed: Worldwide
Company Headquarters Location: Switzerland
Vulnerabilities
Expand All +
CVE-2025-7705
Authentication bypass due to compatibility mode enabled by default
View CVE Details
Affected Products
ABB Busch-Welcome 2 Wire Door Opener Actuator
Vendor:ABB
Product Version:Switch Actuator 4 DU -83330 - All Versions, Switch actuator, door/light 4 DU -83330-500 - All Versions
Product Status:known_affected
Remediations
MitigationThe following actions need to be executed on premise where the respective Busch-Welcomeİ System is installed: ? While the Busch-Welcomeİ System is in operation, toggle the mode switch on the product from ?Door-Open? - to ?Light? ? Mode, wait one second and switch back to ?Door-Open? - Mode. ? Restart the Busch-Welcomeİ System with a Power reset (mains power off and on again). By executing the above steps, the system will recalibrate itself during boot up and will correct the misconfiguration automatically. ABB recommends that customers apply the above listed actions at the earliest convenience.
Relevant CWE: CWE-489 Active Debug Code
Metrics
CVSS Version
Base Score
Base Severity
Vector String
3.1
6.8
MEDIUM
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Acknowledgments
ABB PSIRT reported this vulnerability to CISA.
Notice
The information in this document is subject to change without notice, and should not be construed as a commitment by ABB. ABB provides no warranty, express or implied, including warranties of merchantability and fitness for a particular purpose, for the information contained in this document, and assumes no responsibility for any errors that may appear in this document. In no event shall ABB or any of its suppliers be liable for direct, indirect, special, incidental or consequential damages of any nature or kind arising from the use of this document, or from the use of any hard-ware or software described in this document, even if ABB or its suppliers have been advised of the possibility of such damages. This document and parts hereof must not be reproduced or copied without written permission from ABB, and the contents hereof must not be imparted to a third party nor used for any unauthorized purpose. All rights to registrations and trademarks reside with their respective owners.
Mitigating factors
ABB recommends double check the system handbook of a Busch-Welcomeİ two wire system regarding security advises for the correct installation.
Legal Notice and Terms of Use
This product is provided subject to this Notification (
https://www.cisa.gov/notification) and this Privacy & Use policy (
https://www.cisa.gov/privacy-policy).
Recommended Practices
CISA recommends users take defensive measures to minimize the exploitation risk of these vulnerabilities.
Minimize network exposure for all control system devices and/or systems, and ensure they are not accessible from the internet.
Locate control system networks and remote devices behind firewalls and isolate them from business networks.
When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most recent version available. Also recognize VPN is only as secure as its connected devices.
CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
CISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.
CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets. Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov in the technical information paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.
Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.
Advisory Conversion Disclaimer
This ICSA is a verbatim republication of ABB PSIRT 9AKK108471A4556 from a direct conversion of the vendor's Common Security Advisory Framework (CSAF) advisory. This is republished to CISA's website as a means of increasing visibility and is provided "as-is" for informational purposes only. CISA is not responsible for the editorial or technical accuracy of republished advisories and provides no warranties of any kind regarding any information contained within this advisory. Further, CISA does not endorse any commercial product or service. Please contact ABB PSIRT directly for any questions regarding this advisory.
Revision History
Initial Release Date: 2025-07-21
Date
Revision
Summary
2025-07-21
1
Initial version.
2026-05-28
2
Initial CISA Republication of ABB PSIRT 9AKK108471A4556 advisory
Legal Notice and Terms of Use
https://www.cisa.gov/news-events/ics-advisories/icsa-26-148-04
2026-05-28 12:00 UTC
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* Origin: TCOB1 A Mail Only System (2:263/1)