Stack disclosure via reused NVRAM data length
Published Jan 5, 2023 · Updated Apr 10, 2025
Buffer over-read in the LenovoSetupConfigDxe driver in Lenovo ThinkPad X13s BIOS before 1.47 allows local users to disclose stack memory. The driver lets GetVariable overwrite DataSize, then reuses that length in SetVariable, copying bytes beyond a 49-byte stack buffer into LenovoFunctionConfig NVRAM. Elevated privileges are required to supply the oversized variable; disclosed stack contents can expose firmware memory and assist later DXE attacks.
Summary
What happened
Buffer over-read in the LenovoSetupConfigDxe driver in Lenovo ThinkPad X13s BIOS before 1.47 allows local users to disclose stack memory. The driver lets GetVariable overwrite DataSize, then reuses that length in SetVariable, copying bytes beyond a 49-byte stack buffer into LenovoFunctionConfig NVRAM. Elevated privileges are required to supply the oversized variable; disclosed stack contents can expose firmware memory and assist later DXE attacks.
The record
- CVE
- CVE-2022-4433
- Published
- Jan 5, 2023
- Updated
- Apr 10, 2025
- Vendor
- Lenovo
- Product
- ThinkPad X13s
- Classifications
- CWE-126, CWE-125, 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
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
- Stack memory leak vulnerability in DXE driverproof of concept · unverified
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Technologies
Your stack
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Your stack
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