SMRAM disclosure via unchecked SMI source address
Published Sep 21, 2022 · Updated May 5, 2025
Improper input validation in InsydeH2O kernels 5.0 through 5.5 allows local users to read SMRAM through a software SMI. The FvbServicesRuntimeDxe handler accepts an attacker-controlled source address without checking whether it points into SMRAM, then copies bytes from that address into the communication buffer. Kernel-level access is required; the primitive discloses protected firmware memory but does not itself modify SMRAM or execute code.
Summary
What happened
Improper input validation in InsydeH2O kernels 5.0 through 5.5 allows local users to read SMRAM through a software SMI. The FvbServicesRuntimeDxe handler accepts an attacker-controlled source address without checking whether it points into SMRAM, then copies bytes from that address into the communication buffer. Kernel-level access is required; the primitive discloses protected firmware memory but does not itself modify SMRAM or execute code.
The record
- CVE
- CVE-2022-35896
- Published
- Sep 21, 2022
- Updated
- May 5, 2025
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-20
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Sep 21, 2022CVE publishedPublication date reported by the CVE source.
- May 5, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
Published CVSS scores
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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
- Binarly SMM memory-read technical demonstrationproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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