Local UEFI code execution via stale GetVariable size
Published Feb 16, 2023 · Updated Mar 19, 2025
Stack overflow in Acer Aspire E5-475G BIOS firmware 1.21 allows local users to execute arbitrary code during the UEFI DXE phase. The FpGui function at offset 0x356A8 calls GetVariable twice for DataAddress after setting DataSize to 8, but neither resets the enlarged size nor checks it against the stack buffer. A low-privileged local user can supply an oversized DataAddress value, overwrite the stack frame, hijack control flow, and implant a persistent firmware backdoor.
Summary
What happened
Stack overflow in Acer Aspire E5-475G BIOS firmware 1.21 allows local users to execute arbitrary code during the UEFI DXE phase. The FpGui function at offset 0x356A8 calls GetVariable twice for DataAddress after setting DataSize to 8, but neither resets the enlarged size nor checks it against the stack buffer. A low-privileged local user can supply an oversized DataAddress value, overwrite the stack frame, hijack control flow, and implant a persistent firmware backdoor.
The record
- CVE
- CVE-2022-40080
- Published
- Feb 16, 2023
- Updated
- Mar 19, 2025
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-787, T1542.001, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Feb 16, 2023CVE publishedPublication date reported by the CVE source.
- Mar 19, 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?
What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
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
- FpGui DataAddress stack-overflow proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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