PEI code execution via reused NVRAM length
Published Sep 20, 2022 · Updated May 27, 2025
Stack-based buffer overflow in PlatformInitAdvancedPreMem in AMI Aptio V 5.x allows local users to execute code during the PEI phase. The module reuses one DataSize variable for consecutive SaSetup and CpuSetup GetVariable calls, so an oversized SaSetup value enlarges the subsequent write into a 1,072-byte stack buffer. Exploitation requires privileged modification of protected NVRAM variables or firmware reflashing, and permits boot-stage control, memory disclosure, and SMRAM payload injection.
Summary
What happened
Stack-based buffer overflow in PlatformInitAdvancedPreMem in AMI Aptio V 5.x allows local users to execute code during the PEI phase. The module reuses one DataSize variable for consecutive SaSetup and CpuSetup GetVariable calls, so an oversized SaSetup value enlarges the subsequent write into a 1,072-byte stack buffer. Exploitation requires privileged modification of protected NVRAM variables or firmware reflashing, and permits boot-stage control, memory disclosure, and SMRAM payload injection.
The record
- CVE
- CVE-2022-26873
- Published
- Sep 20, 2022
- Updated
- May 27, 2025
- Vendor
- American Megatrends International
- Product
- Aptio V
- Classifications
- CWE-121, CWE-787, T1542.001
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Sep 20, 2022CVE publishedPublication date reported by the CVE source.
- May 27, 2025Record 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=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.
Weakness, pattern, technique
Public exploit references
- Binarly NVRAM proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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