SMM code execution via unsafe boot-service calls
Published Feb 3, 2022 · Updated Aug 11, 2026
Improper input validation in InsydeH2O StorageSecurityCommandDxe on affected Siemens industrial PCs allows local users to gain SMM execution. The child software-SMI handler calls EFI boot services after their function pointers can be replaced in system memory, redirecting LocateHandleBuffer or HandleProtocol to attacker-controlled code. High-privileged local access is required to alter a boot-service pointer and trigger the handler; successful exploitation executes code above the operating system and can bypass firmware flash protections.
Summary
What happened
Improper input validation in InsydeH2O StorageSecurityCommandDxe on affected Siemens industrial PCs allows local users to gain SMM execution. The child software-SMI handler calls EFI boot services after their function pointers can be replaced in system memory, redirecting LocateHandleBuffer or HandleProtocol to attacker-controlled code. High-privileged local access is required to alter a boot-service pointer and trigger the handler; successful exploitation executes code above the operating system and can bypass firmware flash protections.
The record
- CVE
- CVE-2021-42113
- Published
- Feb 3, 2022
- Updated
- Aug 11, 2026
- Vendor
- Siemens
- Product
- SIMATIC IPC477E PRO
- Classifications
- CWE-20, T1068
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Feb 3, 2022CVE publishedPublication date reported by the CVE source.
- Aug 11, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <V21.01.17
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- BRLY-2021-023 exploitation procedurefunctional · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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