Physical code execution via unvalidated NVRAM pointer
Published Sep 20, 2022 · Updated May 28, 2025
Arbitrary write in the SbPei module in AMI Aptio V 5.x allows physically proximate attackers to execute code during PEI on S3 resume. On S3 resume, EfiPeiEndOfPeiPhaseNotifier trusts the AmiCspGlobalNvsPtrVar NVRAM value as a pointer and writes a fixed byte to that address. Exploitation requires privileged physical access to rewrite SPI flash while the device sleeps or is off, enabling later boot-stage control, memory disclosure, or SMRAM payload injection.
Summary
What happened
Arbitrary write in the SbPei module in AMI Aptio V 5.x allows physically proximate attackers to execute code during PEI on S3 resume. On S3 resume, EfiPeiEndOfPeiPhaseNotifier trusts the AmiCspGlobalNvsPtrVar NVRAM value as a pointer and writes a fixed byte to that address. Exploitation requires privileged physical access to rewrite SPI flash while the device sleeps or is off, enabling later boot-stage control, memory disclosure, or SMRAM payload injection.
The record
- CVE
- CVE-2022-40246
- Published
- Sep 20, 2022
- Updated
- May 28, 2025
- Vendor
- American Megatrends International
- Product
- Aptio V
- Classifications
- CWE-123, T1542.001
- Attack vector
- physical
- Privileges
- admin
Timeline
How it unfolded
- Sep 20, 2022CVE publishedPublication date reported by the CVE source.
- May 28, 2025Record 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=5.x
What conditions does exploitation require?
What is affected?
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.
Public exploit references
- SbPei SPI-flash overwrite reproduction procedureproof of concept · demonstrated
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