Siemens SINEC NMS

Summary

Siemens SINEC NMS versions prior to V4.0 SP3 contain a high-severity authorization bypass vulnerability (CVE-2026-25654) that fails to properly validate user authorization during password reset requests. An authenticated remote attacker can exploit this to reset passwords of any arbitrary user account, compromising the system. Siemens has released a patched version and recommends immediate updates for all affected deployments.

Full text

ICS Advisory Siemens SINEC NMS Release DateApril 21, 2026 Alert CodeICSA-26-111-09 Related topics: Industrial Control System Vulnerabilities, Industrial Control Systems View CSAF Summary SINEC NMS before V4.0 SP3 contains an Authorization Bypass vulnerability that could allow an attacker to bypass authorization checks, leading to the ability to reset the password of any arbitrary user account. Siemens has released a new version for SINEC NMS and recommends to update to the latest version. The following versions of Siemens SINEC NMS are affected: SINEC NMS CVSS Vendor Equipment Vulnerabilities v3 8.8 Siemens Siemens SINEC NMS Authorization Bypass Through User-Controlled Key Background Critical Infrastructure Sectors: Critical Manufacturing Countries/Areas Deployed: Worldwide Company Headquarters Location: Germany Vulnerabilities Expand All + CVE-2026-25654 Affected products do not properly validate user authorization when processing password reset requests. This could allow an authenticated remote attacker to bypass authorization checks, leading to the ability to reset the password of any arbitrary user account. View CVE Details Affected Products Siemens SINEC NMS Vendor:Siemens Product Version:SINEC NMS Product Status:known_affected Remediations MitigationLimit network access to trusted users and systems only Vendor fixUpdate to V4.0 SP3 or later versionhttps://support.industry.siemens.com/cs/ww/en/view/110000760/ Relevant CWE: CWE-639 Authorization Bypass Through User-Controlled Key Metrics CVSS Version Base Score Base Severity Vector String 3.1 8.8 HIGH CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Acknowledgments Siemens ProductCERT reported this vulnerability to CISA. General Recommendations As a general security measure, Siemens strongly recommends to protect network access to devices with appropriate mechanisms. In order to operate the devices in a protected IT environment, Siemens recommends to configure the environment according to Siemens' operational guidelines for Industrial Security (Download: https://www.siemens.com/cert/operational-guidelines-industrial-security), and to follow the recommendations in the product manuals. Additional information on Industrial Security by Siemens can be found at: https://www.siemens.com/industrialsecurity Additional Resources For further inquiries on security vulnerabilities in Siemens products and solutions, please contact the Siemens ProductCERT: https://www.siemens.com/cert/advisories Terms of Use The use of Siemens Security Advisories is subject to the terms and conditions listed on: https://www.siemens.com/productcert/terms-of-use. 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 Siemens ProductCERT SSA-605717 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 Siemens ProductCERT directly for any questions regarding this advisory. Revision History Initial Release Date: 2026-04-14 Date Revision Summary 2026-04-14 1 Publication Date 2026-04-21 2 Initial CISA Republication of Siemens ProductCERT SSA-605717 advisory Legal Notice and Terms of Use This product is provided subject to this Notification and this Privacy & Use policy. Vendor Siemens Tags Sector: Critical Manufacturing Sector Topics: Industrial Control System Vulnerabilities, Industrial Control Systems Please share your thoughts We recently updated our anonymous product survey; we welcome your feedback. Related Advisories Apr 21, 2026 ICS Advisory | ICSA-26-111-04 Siemens Analytics Toolkit Apr 21, 2026 ICS Advisory | ICSA-26-111-02 Siemens RUGGEDCOM CROSSBOW Secure Access Manager Primary Apr 21, 2026 ICS Advisory | ICSA-26-111-03 Siemens SINEC NMS Apr 21, 2026 ICS Advisory | ICSA-26-111-12 SenseLive X3050

Indicators of Compromise

• cve — CVE-2026-25654

Entities