Summary
The products listed below contain a vulnerability that could allow an attacker to boot an operating system or UEFI application signed with that test key, bypassing UEFI Secure Boot protections even when Secure Boot is enabled. Siemens has released new versions for the affected products and recommends to update to the latest versions.
The following versions of Siemens SIMATIC IPCs are affected:
- SIMATIC IPC BX-21A vers:intdot/<31.01.13 (CVE-2026-72895)
- SIMATIC IPC RW-543A vers:intdot/<1.1.4 (CVE-2026-72895)
- SIMATIC IPC227G / IPC277G / IPC277G PRO / IPC327G / IPC377G vers:intdot/<28.01.15 (CVE-2026-72895)
CVSS
Vendor
Equipment
v3 7.7
Siemens
SIMATIC IPC BX-21A
1 Vulnerability
Use of Default Cryptographic Key
Background
- Critical Infrastructure Sectors: Critical Manufacturing, Transportation Systems, Energy, Healthcare and Public Health, Financial Services, Government Services and Facilities
- Countries/Areas Deployed: Worldwide
- Company Headquarters Location: Germany
Vulnerabilities
CVE-2026-72895
A BIOS vendor test key is present in the UEFI Secure Boot key database. This could allow a local attacker with physical or administrative access to the device to boot an operating system or UEFI application signed with that test key, bypassing UEFI Secure Boot protections even when Secure Boot is enabled, potentially leading to a full loss of confidentiality, integrity, and availability of the device.
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3 Affected Products
SIMATIC IPC BX-21A < V31.01.13
Product Status: known_affected
Remediations
Mitigation
Note: After upgrading to the fixed BIOS version, users must load the BIOS default settings. If Secure Boot keys were already provisioned, they must be provisioned again afterwards.
Mitigation
As a temporary mitigation, users can manually remove the test key from the database (e.g., "DO NOT TRUST – AMI Test PK" for RW-543A or "insyde-ElkhartLake" for IPC227G/277G/327G/377G and BX-21A). Note: Loading default settings will restore the test key, so upgrading remains recommended.
Vendor fix
Update to V31.01.13 or later version
SIMATIC IPC RW-543A < V1.1.4
Product Status: known_affected
Remediations
Mitigation
Note: After upgrading to the fixed BIOS version, users must load the BIOS default settings. If Secure Boot keys were already provisioned, they must be provisioned again afterwards.
Mitigation
As a temporary mitigation, users can manually remove the test key from the database (e.g., "DO NOT TRUST – AMI Test PK" for RW-543A or "insyde-ElkhartLake" for IPC227G/277G/327G/377G and BX-21A). Note: Loading default settings will restore the test key, so upgrading remains recommended.
Vendor fix
Update to V1.1.4 or later version
SIMATIC IPC227G / IPC277G / IPC277G PRO / IPC327G / IPC377G < V28.01.15
Product Status: known_affected
Remediations
Mitigation
Note: After upgrading to the fixed BIOS version, users must load the BIOS default settings. If Secure Boot keys were already provisioned, they must be provisioned again afterwards.
Mitigation
As a temporary mitigation, users can manually remove the test key from the database (e.g., "DO NOT TRUST – AMI Test PK" for RW-543A or "insyde-ElkhartLake" for IPC227G/277G/327G/377G and BX-21A). Note: Loading default settings will restore the test key, so upgrading remains recommended.
Vendor fix
Update to V28.01.15 or later version
Additional Metrics
Relevant CWE: CWE-1394 Use of Default Cryptographic Key
CVSS Version
Base Score
Base Severity
Vector String
3.1
7.7
HIGH
CVSS:3.1/AV:L/AC:H/PR:N/UI:R/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.
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
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