View CSAF Summary ABB became aware of vulnerabilities in AC500 V2 listed as affected in the advisory. An attacker who successfully exploited this vulnerability could access fragments of Modbus telegrams that have been sent earlier by that PLC The following versions of ABB AC500 V2 are affected: AC500 V2 <=2.5.2, 2.5.3 CVSS Vendor Equipment Vulnerabilities v3 5.8 ABB ABB AC500 V2 Buffer Over-read Background Critical Infrastructure Sectors: Critical Manufacturing, Energy, Water and Wastewater Countries/Areas Deployed: Worldwide Company Headquarters Location: Switzerland Vulnerabilities Expand All + CVE-2025-7745 Sending unsupported function codes to the AC500 V2 Modbus server might result in invalid responses. Fragments of previous responses might be added to the end of the response. View CVE Details Affected Products ABB AC500 V2 Vendor: ABB Product Version: ABB AC500 V2 <=2.5.2 Product Status: fixed, known_affected Remediations Vendor fix The vulnerabilities have been resolved in the following product versions: AC500 V2 firmware version 2.5.3 (released in 2016) and later Relevant CWE: CWE-126 Buffer Over-read Metrics CVSS Version Base Score Base Severity Vector String 3.1 5.8 MEDIUM CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N Acknowledgments Reid Wightman of Dragos. Inc reported these vulnerabilities to Schneider Electric. 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 hardware 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 Mitigating factors describe conditions and circumstances that make an attack that exploits the vulnerability difficult or less likely to succeed. Regarding this vulnerability it is recommended to • Do not use the Modbus server for sending any sensitive data, as fragments might be accessible even after the initial sending of the response • Only use supported Modbus function codes, as invalid responses to unsupported function codes might have negative effects on the requesting Modbus client. Refer to section “General security recommendations” for further advise on how to keep your system secure. 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 3ADR011432 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: 2025-07-23 Date Revision Summary 2025-07-23 1 Initial version. 2026-05-22 2 Minor correction to the affected product version in the product tree. 2026-05-26 3 Initial CISA Republication of ABB PSIRT 3ADR011432 advisory Legal Notice and Terms of Use