S3 corruption and disclosure via SPI ROM race
Published May 9, 2023 · Updated Jan 28, 2025
A TOCTOU race in the AMD Secure Processor bootloader on affected EPYC, Ryzen, and Threadripper processors allows attackers to corrupt S3 data. The bootloader reads SPI ROM data into memory without ensuring that the underlying ROM remains unchanged before the data is subsequently used. Exploitation requires winning that race during bootloader processing; successful tampering corrupts S3 resume data and discloses information.
Summary
What happened
A TOCTOU race in the AMD Secure Processor bootloader on affected EPYC, Ryzen, and Threadripper processors allows attackers to corrupt S3 data. The bootloader reads SPI ROM data into memory without ensuring that the underlying ROM remains unchanged before the data is subsequently used. Exploitation requires winning that race during bootloader processing; successful tampering corrupts S3 resume data and discloses information.
The record
- CVE
- CVE-2021-26356
- Published
- May 9, 2023
- Updated
- Jan 28, 2025
- Vendor
- Advanced Micro Devices, Inc.
- Product
- AMD Ryzen Threadripper PRO 5000WX Processors
- Classifications
- CWE-367, T1495
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 9, 2023CVE publishedPublication date reported by the CVE source.
- Jan 28, 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=various
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
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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