Stack disclosure via unchecked NVRAM write length
Published Jan 5, 2023 · Updated Apr 10, 2025
Buffer over-read in the Lenovo ThinkPad X13s BIOS before 1.47 allows local users with elevated privileges to disclose stack memory. The LenovoRemoteConfigUpdateDxe driver passes a GetVariable-modified DataSize to SetVariable without resetting it, writing bytes beyond the 49-byte LenovoFunctionConfig buffer into NVRAM. Exploitation requires privileged local control of an oversized LenovoFunctionConfig NVRAM value; disclosure is limited to adjacent stack contents made readable from that variable.
Summary
What happened
Buffer over-read in the Lenovo ThinkPad X13s BIOS before 1.47 allows local users with elevated privileges to disclose stack memory. The LenovoRemoteConfigUpdateDxe driver passes a GetVariable-modified DataSize to SetVariable without resetting it, writing bytes beyond the 49-byte LenovoFunctionConfig buffer into NVRAM. Exploitation requires privileged local control of an oversized LenovoFunctionConfig NVRAM value; disclosure is limited to adjacent stack contents made readable from that variable.
The record
- CVE
- CVE-2022-4435
- Published
- Jan 5, 2023
- Updated
- Apr 10, 2025
- Vendor
- Lenovo
- Product
- ThinkPad X13s
- Classifications
- CWE-125, CWE-126, T1005
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Jan 5, 2023CVE publishedPublication date reported by the CVE source.
- Apr 10, 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?
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- Affected versionversion=Versions prior to 1.47
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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