Siemens Desigo CC

Summary

A critical stack-based buffer overflow vulnerability (CVE-2025-15467) in OpenSSL affects Siemens Desigo CC building management systems across versions V7, V8, and V9 (prior to 9.0.1). The flaw allows remote attackers to trigger denial of service or potentially execute code by sending maliciously crafted CMS AuthEnvelopedData messages with oversized AEAD parameters. Patches are available for V9 and V8, with V7 still lacking a fix.

Full text

ICS Advisory Siemens Desigo CC Release DateJuly 28, 2026 Alert CodeICSA-26-209-01 Related topics: Industrial Control System Vulnerabilities , Industrial Control Systems View CSAF Summary OpenSSL has published a stack based buffer overflow vulnerability that allows a remote attacker to cause a denial of service (DoS) or potentially allow for remote code execution. Siemens has released new versions for several affected products and recommends to update to the latest versions. Siemens is preparing further fix versions and recommends countermeasures for products where fixes are not, or not yet available. The following versions of Siemens Desigo CC are affected: Desigo CC family V7 vers:all/* (CVE-2025-15467) Desigo CC family V8 vers:all/* (CVE-2025-15467) Desigo CC family V9 vers:intdot/<9.0.1 (CVE-2025-15467) CVSS Vendor Equipment Vulnerabilities v3 9.8 Siemens Siemens Desigo CC Out-of-bounds Write Background Critical Infrastructure Sectors: Critical Manufacturing Countries/Areas Deployed: Worldwide Company Headquarters Location: Germany Vulnerabilities Expand All + CVE-2025-15467 Issue summary: Parsing CMS AuthEnvelopedData message with maliciously crafted AEAD parameters can trigger a stack buffer overflow. Impact summary: A stack buffer overflow may lead to a crash, causing Denial of Service, or potentially remote code execution. When parsing CMS AuthEnvelopedData 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. Applications and services that parse untrusted CMS or PKCS#7 content using AEAD ciphers (e.g., S/MIME AuthEnvelopedData with AES-GCM) are vulnerable. 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. The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this issue, as the CMS implementation is outside the OpenSSL FIPS module boundary. OpenSSL 3.6, 3.5, 3.4, 3.3 and 3.0 are vulnerable to this issue. OpenSSL 1.1.1 and 1.0.2 are not affected by this issue. View CVE Details Affected Products Siemens Desigo CC Vendor:Siemens Product Version:Desigo CC family V7, Desigo CC family V8, Desigo CC family V9 < V9.0.1 Product Status:known_affected Remediations None availableCurrently no fix is available Vendor fixUpdate to V9.0 QU1 or later versionhttps://support.industry.siemens.com/cs/ww/en/view/110002555/ Vendor fixUpdate to patch V8.0 QU2.0021 Vendor fixhttps://support.industry.siemens.com/cs/ww/en/view/109989041/ 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 Acknowledgments Siemens ProductCERT reported this vulnerability to CISA. General Recommendations Operators of critical power systems (e.g. TSOs or DSOs) worldwide are usually required by regulations to build resilience into the power grids by applying multi-level redundant secondary protection schemes. It is therefore recommended that the operators check whether appropriate resilient protection measures are in place. The risk of cyber incidents impacting the grid's reliability can thus be minimized by virtue of the grid design. Siemens strongly recommends applying the provided security updates using the corresponding tooling and documented procedures made available with the product. If supported by the product, an automated means to apply the security updates across multiple product instances may be used. Siemens strongly recommends prior validation of any security update before being applied, and supervision by trained staff of the update process in the target environment. As a general security measure Siemens strongly recommends to protect network access with appropriate mechanisms (e.g. firewalls, segmentation, VPN). It is advised to configure the environment according to our operational guidelines in order to run the devices in a protected IT environment. Recommended security guidelines can be found at: https://www.siemens.com/gridsecurity 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-734552 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 2026-07-28 2 Initial CISA Republication of Siemens ProductCERT SSA-734552 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 28, 2026 ICS Advisory | ICSA-26-209-03 Siemens SIMATIC S7-PLCSIM Advanced Jul 28, 2026 ICS Advisory | ICSA-26-209-04 Siemens SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP Jul 28, 2026 ICS Advisory | ICSA-26-209-07 ABB KNX Update Tool Jul 28, 20

Indicators of Compromise

• cve — CVE-2025-15467

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