Siemens Opcenter X

Summary

Siemens Opcenter X versions prior to V2604 contain a critical authentication bypass vulnerability (CVE-2026-56451). This flaw allows unauthenticated remote attackers to forge JSON Web Tokens (JWT), bypass authentication, and gain full unauthorized access to the application, including administrative privileges. Siemens has released version V2604 and strongly recommends updating to the latest version to mitigate this risk.

Full text

ICS Advisory Siemens Opcenter X Release DateJuly 21, 2026 Alert CodeICSA-26-202-03 Related topics: Industrial Control System Vulnerabilities , Industrial Control Systems View CSAF Summary Opcenter X before V2604 contain an authentication bypass vulnerability that could allow an attacker to gain full unauthorized access to the application. Siemens has released a new version for Opcenter X and recommends to update to the latest version. The following versions of Siemens Opcenter X are affected: Opcenter X vers:intdot/<2604 CVSS Vendor Equipment Vulnerabilities v3 10 Siemens Siemens Opcenter X Improper Verification of Cryptographic Signature Background Critical Infrastructure Sectors: Critical Manufacturing Countries/Areas Deployed: Worldwide Company Headquarters Location: Germany Vulnerabilities Expand All + CVE-2026-56451 Affected applications do not properly validate the algorithm specified in the JSON Web Token (JWT) header. This could allow an unauthenticated remote attacker to forge arbitrary JWT, bypass authentication mechanisms and impersonate any user including administrative accounts, potentially gaining full unauthorized access to the application. View CVE Details Affected Products Siemens Opcenter X Vendor:Siemens Product Version:Opcenter X < V2604 Product Status:known_affected Remediations Vendor fixUpdate to V2604 or later versionhttps://support.sw.siemens.com/product/206159703/ Relevant CWE: CWE-347 Improper Verification of Cryptographic Signature Metrics CVSS Version Base Score Base Severity Vector String 3.1 10 CRITICAL CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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-096828 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: 2026-07-14 Date Revision Summary 2026-07-14 1 Publication Date 2026-07-21 2 Initial CISA Republication of Siemens ProductCERT SSA-096828 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 Jul 21, 2026 ICS Advisory | ICSA-26-202-01 Tycon Systems TPDIN-Monitor-WEB2 Jul 21, 2026 ICS Advisory | ICSA-26-202-10 Rockwell Automation Studio 5000 Logix Designer Jul 21, 2026 ICS Advisory | ICSA-26-202-02 Siemens RUGGEDCOM APE1808 with Palo Alto Networks Virtual NGFW Jul 21, 2026 ICS Advisory | ICSA-26-202-05 Siemens IAM Client

Indicators of Compromise

• cve — CVE-2026-56451

Entities