SMM code execution via unchecked pointer range
Published Feb 3, 2022 · Updated Aug 11, 2026
Memory corruption in InsydeH2O SdHostDriver kernels 5.0 through 5.5 allows local users to execute arbitrary code in SMM. Its SWSMI handler accepts an unsafe pointer because a numeric range comparison omits a minimum-bound check, enabling reads or writes in SMRAM. High privileges and local code execution are required; successful exploitation moves execution from ring 0 into isolated ring -2 firmware context.
Summary
What happened
Memory corruption in InsydeH2O SdHostDriver kernels 5.0 through 5.5 allows local users to execute arbitrary code in SMM. Its SWSMI handler accepts an unsafe pointer because a numeric range comparison omits a minimum-bound check, enabling reads or writes in SMRAM. High privileges and local code execution are required; successful exploitation moves execution from ring 0 into isolated ring -2 firmware context.
The record
- CVE
- CVE-2021-41838
- Published
- Feb 3, 2022
- Updated
- Aug 11, 2026
- Vendor
- Siemens
- Product
- SIMATIC IPC477E PRO
- Classifications
- CWE-119, 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
Compare your product and version with the public record. A matching version still requires validation against your environment.
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
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo