CVE-2021-26356

Name: CVE-2021-26356
Creator: NVD / NIST
Published: 2023-05-09T19:15:10.737+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.4/10EPSS 0.40%

Last modified Jun 17, 2026

CVE-2021-26356 is a high-severity vulnerability rated 7.4/10 on the CVSS scale. A TOCTOU in ASP bootloader may allow an attacker to tamper with the SPI ROM following data read to memory potentially resulting in S3 data corruption and information disclosure. . EPSS estimates a 0.40% chance of exploitation in the next 30 days.

Description

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

Metrics

CVSS 3.1

7.4/10

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS Probability

0.40%

31.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Amd	Epyc 7001 Firmware	< naplespi_1.0.0.h
Amd	Epyc 7251 Firmware	< naplespi_1.0.0.h
Amd	Epyc 7261 Firmware	< naplespi_1.0.0.h
Amd	Epyc 7281 Firmware	< naplespi_1.0.0.h
Amd	Epyc 7301 Firmware	< naplespi_1.0.0.h
Amd	Epyc 7351 Firmware	< naplespi_1.0.0.h
Amd	Epyc 7351p Firmware	< naplespi_1.0.0.h
Amd	Epyc 7371 Firmware	< naplespi_1.0.0.h
Amd	Epyc 7401 Firmware	< naplespi_1.0.0.h
Amd	Epyc 7401p Firmware	< naplespi_1.0.0.h
Amd	Epyc 7451 Firmware	< naplespi_1.0.0.h
Amd	Epyc 7501 Firmware	< naplespi_1.0.0.h
Amd	Epyc 7551 Firmware	< naplespi_1.0.0.h
Amd	Epyc 7551p Firmware	< naplespi_1.0.0.h
Amd	Epyc 7601 Firmware	< naplespi_1.0.0.h
Amd	Epyc 7002 Firmware	< romepi_1.0.0.d
Amd	Epyc 7232p Firmware	< romepi_1.0.0.d
Amd	Epyc 7252 Firmware	< romepi_1.0.0.d
Amd	Epyc 7262 Firmware	< romepi_1.0.0.d
Amd	Epyc 7272 Firmware	< romepi_1.0.0.d
Amd	Epyc 7282 Firmware	< romepi_1.0.0.d
Amd	Epyc 7302 Firmware	< romepi_1.0.0.d
Amd	Epyc 7302p Firmware	< romepi_1.0.0.d
Amd	Epyc 7352 Firmware	< romepi_1.0.0.d
Amd	Epyc 7402 Firmware	< romepi_1.0.0.d
Amd	Epyc 7402p Firmware	< romepi_1.0.0.d
Amd	Epyc 7452 Firmware	< romepi_1.0.0.d
Amd	Epyc 7502 Firmware	< romepi_1.0.0.d
Amd	Epyc 7532 Firmware	< romepi_1.0.0.d
Amd	Epyc 7542 Firmware	< romepi_1.0.0.d
Amd	Epyc 7552 Firmware	< romepi_1.0.0.d
Amd	Epyc 7642 Firmware	< romepi_1.0.0.d
Amd	Epyc 7662 Firmware	< romepi_1.0.0.d
Amd	Epyc 7702 Firmware	< romepi_1.0.0.d
Amd	Epyc 7702p Firmware	< romepi_1.0.0.d
Amd	Epyc 7f32 Firmware	< romepi_1.0.0.d
Amd	Epyc 7f52 Firmware	< romepi_1.0.0.d
Amd	Epyc 7f72 Firmware	< romepi_1.0.0.d
Amd	Epyc 7h12 Firmware	< romepi_1.0.0.d
Amd	Epyc 7742 Firmware	< romepi_1.0.0.d
Amd	Epyc 7773x Firmware	< milanpi_1.0.0.6
Amd	Epyc 7763 Firmware	< milanpi_1.0.0.6
Amd	Epyc 7713p Firmware	< milanpi_1.0.0.6
Amd	Epyc 7713 Firmware	< milanpi_1.0.0.6
Amd	Epyc 7663 Firmware	< milanpi_1.0.0.6
Amd	Epyc 7643 Firmware	< milanpi_1.0.0.6
Amd	Epyc 75f3 Firmware	< milanpi_1.0.0.6
Amd	Epyc 7573x Firmware	< milanpi_1.0.0.6
Amd	Epyc 7543p Firmware	< milanpi_1.0.0.6
Amd	Epyc 7543 Firmware	< milanpi_1.0.0.6

Showing 50 of 98 affected configurations. See NVD for the full list.

References

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

Timeline

Published: May 9, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-26356?

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

How severe is CVE-2021-26356?

CVE-2021-26356 has a CVSS score of 7.4/10 (HIGH severity). The EPSS model estimates a 0.40% probability of exploitation in the next 30 days.

How do I fix CVE-2021-26356?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-26356?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST