Arbitrary code execution via SMM buffer race
Published Aug 13, 2024 · Updated Mar 18, 2025
A TOCTOU race in AMD processor SMM firmware allows local users with ring0 privileges and firmware-shell access to execute arbitrary code. The SMM handler validates a communications buffer, then uses it after ring0 code can modify its contents between the check and use. Exploitation requires both ring0 privileges and access to the BIOS menu or UEFI shell, and code executes in SMM.
Summary
What happened
A TOCTOU race in AMD processor SMM firmware allows local users with ring0 privileges and firmware-shell access to execute arbitrary code. The SMM handler validates a communications buffer, then uses it after ring0 code can modify its contents between the check and use. Exploitation requires both ring0 privileges and access to the BIOS menu or UEFI shell, and code executes in SMM.
The record
- CVE
- CVE-2023-20578
- Published
- Aug 13, 2024
- Updated
- Mar 18, 2025
- Vendor
- Advanced Micro Devices, Inc.
- Product
- AMD Ryzen™ 7000 Series Desktop Processors
- Classifications
- CWE-367, CAPEC-29, CAPEC-27, T1068
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Aug 13, 2024CVE publishedPublication date reported by the CVE source.
- Mar 18, 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?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
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
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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