View CSAF Summary ABB became aware of vulnerability in the products versions listed as affected in the advisory. An update is available that resolves publicly reported vulnerability. An attacker who successfully exploited these vulnerabilities could cause a crash, denial-of-service (DoS), or potentially remote code execution. The following versions of ABB AC500 V3 Stack Buffer Overflow in Cryptographic Message Syntax are affected: AC500 V3 PM5xxx 3.9.0, 3.9.0_HF1 CVSS Vendor Equipment Vulnerabilities v3 9.8 ABB ABB AC500 V3 Stack Buffer Overflow in Cryptographic Message Syntax Out-of-bounds Write Background Critical Infrastructure Sectors: Chemical, Critical Manufacturing, Energy, Water and Wastewater Countries/Areas Deployed: Worldwide Company Headquarters Location: Switzerland Vulnerabilities Expand All + CVE-2025-15467 When parsing CMS (Auth)EnvelopedData structures that use AEAD ciphers such as AES-GCM, the IV (Initialization Vector) encoded in the ASN.1 parameters is copied into a fixed-size stack buffer without verifying that its length fits the destination. An attacker can supply a crafted CMS message with an oversized IV, causing a stack-based out-of-bounds write before any authentication or tag verification occurs. Because the overflow occurs prior to authentication, no valid key material is required to trigger it. While exploitability to remote code execution depends on platform and toolchain mitigations, the stack-based write primitive represents a severe risk. View CVE Details Affected Products ABB AC500 V3 Stack Buffer Overflow in Cryptographic Message Syntax Vendor: ABB Product Version: ABB AC500 V3 PM5xxx Firmware Version 3.9.0 Product Status: fixed, known_affected Remediations Vendor fix The problem is corrected in the following product version: - AC500 V3 firmware version 3.9.0 HF1 ABB recommends that customers apply the update at earliest convenience. This firmware version is released for all AC500 V3 PLC types and available for download from the ABB library. https://search.abb.com/library/Download.aspx?DocumentID=3ADR011537&LanguageCode=en&DocumentPartId=&Action=Launch Mitigation Refer to section “General security recommendations” for further advise on how to keep your system secure. Workaround No workarounds are available Relevant CWE: CWE-787 Out-of-bounds Write Metrics CVSS Version Base Score Base Severity Vector String 3.1 9.8 CRITICAL CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C 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 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. Frequently Asked Questions What causes the vulnerability? - Parsing CMS AuthEnvelopedData or EnvelopedData message with maliciously crafted AEAD parameters can trigger a stack buffer overflow. What is AC500 V3? - The AC500 V3 is a scalable range of Programmable Logic Controller (PLC). It provides solutions for small, medium and high-end applications. The AC500 V3 platform offers different performance levels and is the ideal choice for high availability, extreme environments, condition monitoring, motion control or safety solutions. It offers interoperability and compatibility in hardware and software from compact PLCs up to high end and safety PLCs. What might an attacker use the vulnerability to do? - An attacker who successfully exploited these vulnerabilities could cause a crash, denial-of-service (DoS), or potentially remote code execution. How could an attacker exploit the vulnerability? - Refer to section “Vulnerability severity and details“. Could the vulnerability be exploited remotely? - Yes, an attacker who has network access to an affected system node could exploit the vulnerabilities. Recommended practices include that process control systems are physically protected, have no direct connections to the Internet, and are separated from other networks by means of a firewall system that has a minimal number of ports exposed. When this security advisory was issued, had this vulnerability been publicly disclosed? - Yes, the vulnerabilities have been publicly disclosed. When this security advisory was issued, had ABB received any reports that this vulnerability was being exploited? - No, ABB had not received any information indicating that this vulnerability had been exploited when this security advisory was originally issued. 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 3ADR011536 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: 2026-03-12 Date Revision Summary 2026-03-12 1 Initial version. 2026-05-12 2 Initial CISA Republication of ABB PSIRT 3ADR011536 advisory Legal Notice and Terms of Use

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