CVEs-PoC/2021/CVE-2021-26356.md

### [CVE-2021-26356](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-26356)
![](https://img.shields.io/static/v1?label=Product&message=1st%20Gen%20AMD%20EPYC%E2%84%A2%20Processors&color=blue)
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![](https://img.shields.io/static/v1?label=Product&message=AMD%20Ryzen%E2%84%A2%205000%20Series%20Desktop%20Processors%20%E2%80%9CVermeer%E2%80%9D%20AM4&color=blue)
![](https://img.shields.io/static/v1?label=Product&message=Ryzen%E2%84%A2%203000%20Series%20Desktop%20Processors%20%E2%80%9CMatisse%E2%80%9D%20AM4&color=blue)
![](https://img.shields.io/static/v1?label=Product&message=Ryzen%E2%84%A2%20Threadripper%E2%84%A2%20PRO%20Processors%20%E2%80%9CCastle%20Peak%E2%80%9D%20WS&color=blue)
![](https://img.shields.io/static/v1?label=Product&message=Ryzen%E2%84%A2%20Threadripper%E2%84%A2%20PRO%20Processors%20%E2%80%9CChagall%E2%80%9D%20WS&color=blue)
![](https://img.shields.io/static/v1?label=Version&message=various%20%20&color=brightgreen)
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### Description

A TOCTOU in ASP bootloader may allow an attackerto tamper with the SPI ROM following data read to memory potentially resultingin S3 data corruption and information disclosure.

### POC

#### Reference
- https://www.amd.com/en/corporate/product-security/bulletin/AMD-SB-3001
- https://www.amd.com/en/corporate/product-security/bulletin/AMD-SB-4001

#### Github
No PoCs found on GitHub currently.