Original Article Summary

View CSAF Summary Successful exploitation of these vulnerabilities could allow an attacker to deliver an unauthorized update, execute code, or extract credentials to allow the attacker to impersonate a privileged client. The following versions of Wärtsilä FOS-Onboard are affected: FOS-Onboard 5.07.0923.01 (CVE-2026-78225, CVE-2026-81855) CVSS Vendor Equipment Vulnerabilities v3 9.1 Wärtsilä Wärtsilä FOS-Onboard Use of Hard-coded Cryptographic Key Background Critical Infrastructure Sectors: Transportation Systems Countries/Areas Deployed: Worldwide Company Headquarters Location: Finland Vulnerabilities Expand All + CVE-2026-78225 A hardcoded cryptographic server key vulnerability exists in the deployer-ng Update Controller component of Wärtsilä FOS-Onboard. View CVE Details Affected Products Wärtsilä FOS-Onboard Vendor: Wärtsilä Product Version: Wärtsilä FOS-Onboard: 5.07.0923.01 Product Status: known_affected Remediations Mitigation Wärtsilä states that the vulnerabilities are not exploitable when the product is installed as recommended, and has developed a security patch. Users are also directed to contact Wärtsilä to obtain and install the patch. To obtain and install the latest patch, contact Wärtsilä: https://www.wartsila.com/services-catalogue/engine-services-4-stroke/wartsila-ics-patch-deployment#contact Relevant CWE: CWE-321 Use of Hard-coded Cryptographic Key Metrics CVSS Version Base Score Base Severity Vector String 3.1 9 CRITICAL CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H 4.0 9.5 CRITICAL CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H CVE-2026-81855 A hardcoded cryptographic client authentication key vulnerability exists in the robot testing framework component of Wärtsilä FOS-Onboard. View CVE Details Affected Products Wärtsilä FOS-Onboard Vendor: Wärtsilä Product Version: Wärtsilä FOS-Onboard: 5.07.0923.01 Product Status: known_affected Remediations Mitigation Wärtsilä states that the vulnerabilities are not exploitable when the product is installed as recommended, and has developed a security patch. Users are also directed to contact Wärtsilä to obtain and install the patch. To obtain and install the latest patch, contact Wärtsilä: https://www.wartsila.com/services-catalogue/engine-services-4-stroke/wartsila-ics-patch-deployment#contact Relevant CWE: CWE-321 Use of Hard-coded Cryptographic Key Metrics CVSS Version Base Score Base Severity Vector String 3.1 9.1 CRITICAL CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N 4.0 9.3 CRITICAL CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N Acknowledgments Cydome Security Ltd reported these vulnerabilities to Wärtsilä and CISA 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 risk of exploitation of these vulnerabilities. Minimize network exposure for all control system devices and/or systems, ensuring they are not accessible from the internet. Locate control system networks and remote devices behind firewalls and isolating 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 current version available. Also recognize VPN is only as secure as the 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/ics. 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/ics 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. CISA also recommends users take the following measures to protect themselves from social engineering attacks: Do not click web links or open attachments in unsolicited email messages. Refer to Recognizing and Avoiding Email Scams for more information on avoiding email scams. Refer to Avoiding Social Engineering and Phishing Attacks for more information on social engineering attacks. No known public exploitation specifically targeting these vulnerabilities has been reported to CISA at this time. Revision History Initial Release Date: 2026-09-15 Date Revision Summary 2026-09-15 1 Initial Publication Legal Notice and Terms of Use