# What is CVE-2021-26356? > CVE-2021-26356 is a high-severity flaw (CVSS 7.4) in Epyc 7001 Firmware from Amd, published on 9 May 2023. It is not on the list of flaws known to be exploited today. The latest forecast puts its chance of use in the next 30 days at 0.4%. If you run an affected version, plan in the vendor’s fix. Canonical page: https://www.precursorintelligence.com/what-is/cve-2021-26356 ## At a glance - **Verdict:** Plan it in. No sign of exploitation and a low forecast. Patch it in your normal update cycle. - **Precursor Intelligence risk score:** 47 out of 100 (Medium); action: Plan remediation. Kept up to date as the evidence changes. - **Severity:** High (CVSS 7.4 out of 10) - **Known to be exploited:** No, not on the list of flaws known to be exploited today - **Chance of use in the next 30 days:** 0.4% (latest exploit-likelihood forecast) - **Published:** 9 May 2023 - **Record last updated:** 28 January 2025 - **Main product:** Epyc 7001 Firmware from Amd - **Affected products:** 196 ## What is CVE-2021-26356? In plain terms It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can read data and change data. ### The official 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. ### What kind of flaw is it? - CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition ### How an attack on it works - Where an attacker can be: Anywhere on the internet - How hard it is to pull off: Hard: conditions must line up - Login needed first: No login needed - Does someone have to click: No, nobody has to do anything - What an attacker gets: Can read data and change data Severity vector: `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N` ## Is CVE-2021-26356 being exploited? Not that we know of It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 0.4%. That can change at any time, which is why we keep watching. Exploit likelihood over the last 7 days: 0.4%, 0.4%, 0.4%, 0.4%, 0.4%, 0.4%, 0.4%. ### Timeline - 9 May 2023: Published - 28 January 2025: Record last updated ### How Precursor Intelligence ranks it CVE-2021-26356 scores **47 out of 100 (Medium)**, with the action "Plan remediation". Every published flaw gets a risk score from 0 to 100, kept up to date as the evidence changes. Four things go into the score, from the one that counts most to the ones that count less: - Evidence it is being exploited: biggest factor - How severe it is: strong factor - How widely exposed it is: smaller factor - Threat activity around it: smaller factor 85 and above is Critical. Anything confirmed as exploited is always marked for an emergency patch, whatever its score. When this flaw matches software you track, it lands in your list with its score and the reasons behind it. ## Who is affected by CVE-2021-26356? The published record lists 196 products. Versions are as published: "before naplespi_1.0.0.h" means every version up to, but not including, naplespi_1.0.0.h. - [Epyc 7001 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7001_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before naplespi_1.0.0.h - [Epyc 7001](https://www.precursorintelligence.com/product/amd/epyc_7001) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7002](https://www.precursorintelligence.com/product/amd/epyc_7002) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7002 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7002_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 7232p](https://www.precursorintelligence.com/product/amd/epyc_7232p) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7232p Firmware](https://www.precursorintelligence.com/product/amd/epyc_7232p_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 7251](https://www.precursorintelligence.com/product/amd/epyc_7251) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7251 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7251_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before naplespi_1.0.0.h - [Epyc 7252](https://www.precursorintelligence.com/product/amd/epyc_7252) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7252 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7252_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 7261](https://www.precursorintelligence.com/product/amd/epyc_7261) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7261 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7261_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before naplespi_1.0.0.h - [Epyc 7262](https://www.precursorintelligence.com/product/amd/epyc_7262) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7262 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7262_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 7272](https://www.precursorintelligence.com/product/amd/epyc_7272) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7272 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7272_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 7281](https://www.precursorintelligence.com/product/amd/epyc_7281) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7281 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7281_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before naplespi_1.0.0.h - [Epyc 7282](https://www.precursorintelligence.com/product/amd/epyc_7282) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7282 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7282_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 72f3](https://www.precursorintelligence.com/product/amd/epyc_72f3) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 72f3 Firmware](https://www.precursorintelligence.com/product/amd/epyc_72f3_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before milanpi_1.0.0.6 - [Epyc 7301](https://www.precursorintelligence.com/product/amd/epyc_7301) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7301 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7301_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before naplespi_1.0.0.h - [Epyc 7302](https://www.precursorintelligence.com/product/amd/epyc_7302) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7302 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7302_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 7302p](https://www.precursorintelligence.com/product/amd/epyc_7302p) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7302p Firmware](https://www.precursorintelligence.com/product/amd/epyc_7302p_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 7313](https://www.precursorintelligence.com/product/amd/epyc_7313) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7313 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7313_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before milanpi_1.0.0.6 - [Epyc 7313p](https://www.precursorintelligence.com/product/amd/epyc_7313p) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7313p Firmware](https://www.precursorintelligence.com/product/amd/epyc_7313p_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before milanpi_1.0.0.6 - [Epyc 7343](https://www.precursorintelligence.com/product/amd/epyc_7343) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7343 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7343_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before milanpi_1.0.0.6 - [Epyc 7351](https://www.precursorintelligence.com/product/amd/epyc_7351) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7351 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7351_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before naplespi_1.0.0.h - [Epyc 7351p](https://www.precursorintelligence.com/product/amd/epyc_7351p) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7351p Firmware](https://www.precursorintelligence.com/product/amd/epyc_7351p_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before naplespi_1.0.0.h - [Epyc 7352](https://www.precursorintelligence.com/product/amd/epyc_7352) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7352 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7352_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 7371](https://www.precursorintelligence.com/product/amd/epyc_7371) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7371 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7371_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before naplespi_1.0.0.h - [Epyc 7373x](https://www.precursorintelligence.com/product/amd/epyc_7373x) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7373x Firmware](https://www.precursorintelligence.com/product/amd/epyc_7373x_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before milanpi_1.0.0.6 - [Epyc 7401](https://www.precursorintelligence.com/product/amd/epyc_7401) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7401 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7401_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before naplespi_1.0.0.h - [Epyc 7401p](https://www.precursorintelligence.com/product/amd/epyc_7401p) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7401p Firmware](https://www.precursorintelligence.com/product/amd/epyc_7401p_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before naplespi_1.0.0.h - [Epyc 7402](https://www.precursorintelligence.com/product/amd/epyc_7402) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7402 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7402_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 7402p](https://www.precursorintelligence.com/product/amd/epyc_7402p) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7402p Firmware](https://www.precursorintelligence.com/product/amd/epyc_7402p_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 7413](https://www.precursorintelligence.com/product/amd/epyc_7413) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7413 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7413_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before milanpi_1.0.0.6 - [Epyc 7443](https://www.precursorintelligence.com/product/amd/epyc_7443) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7443 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7443_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before milanpi_1.0.0.6 - [Epyc 7443p](https://www.precursorintelligence.com/product/amd/epyc_7443p) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7443p Firmware](https://www.precursorintelligence.com/product/amd/epyc_7443p_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before milanpi_1.0.0.6 - [Epyc 7451](https://www.precursorintelligence.com/product/amd/epyc_7451) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7451 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7451_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before naplespi_1.0.0.h - [Epyc 7452](https://www.precursorintelligence.com/product/amd/epyc_7452) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7452 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7452_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 7453](https://www.precursorintelligence.com/product/amd/epyc_7453) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7453 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7453_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before milanpi_1.0.0.6 - [Epyc 7473x](https://www.precursorintelligence.com/product/amd/epyc_7473x) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7473x Firmware](https://www.precursorintelligence.com/product/amd/epyc_7473x_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before milanpi_1.0.0.6 - [Epyc 74f3](https://www.precursorintelligence.com/product/amd/epyc_74f3) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 74f3 Firmware](https://www.precursorintelligence.com/product/amd/epyc_74f3_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before milanpi_1.0.0.6 - [Epyc 7501](https://www.precursorintelligence.com/product/amd/epyc_7501) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7501 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7501_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before naplespi_1.0.0.h - [Epyc 7502](https://www.precursorintelligence.com/product/amd/epyc_7502) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7502 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7502_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 7513](https://www.precursorintelligence.com/product/amd/epyc_7513) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7513 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7513_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before milanpi_1.0.0.6 - [Epyc 7532](https://www.precursorintelligence.com/product/amd/epyc_7532) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7532 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7532_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 7542](https://www.precursorintelligence.com/product/amd/epyc_7542) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7542 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7542_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 7543](https://www.precursorintelligence.com/product/amd/epyc_7543) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7543 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7543_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before milanpi_1.0.0.6 - [Epyc 7543p](https://www.precursorintelligence.com/product/amd/epyc_7543p) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7543p Firmware](https://www.precursorintelligence.com/product/amd/epyc_7543p_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before milanpi_1.0.0.6 - [Epyc 7551](https://www.precursorintelligence.com/product/amd/epyc_7551) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7551 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7551_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before naplespi_1.0.0.h - [Epyc 7551p](https://www.precursorintelligence.com/product/amd/epyc_7551p) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7551p Firmware](https://www.precursorintelligence.com/product/amd/epyc_7551p_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before naplespi_1.0.0.h - [Epyc 7552](https://www.precursorintelligence.com/product/amd/epyc_7552) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7552 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7552_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 7573x](https://www.precursorintelligence.com/product/amd/epyc_7573x) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7573x Firmware](https://www.precursorintelligence.com/product/amd/epyc_7573x_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before milanpi_1.0.0.6 - [Epyc 75f3](https://www.precursorintelligence.com/product/amd/epyc_75f3) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 75f3 Firmware](https://www.precursorintelligence.com/product/amd/epyc_75f3_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before milanpi_1.0.0.6 - [Epyc 7601](https://www.precursorintelligence.com/product/amd/epyc_7601) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7601 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7601_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before naplespi_1.0.0.h - [Epyc 7642](https://www.precursorintelligence.com/product/amd/epyc_7642) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7642 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7642_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 7643](https://www.precursorintelligence.com/product/amd/epyc_7643) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7643 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7643_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before milanpi_1.0.0.6 - [Epyc 7662](https://www.precursorintelligence.com/product/amd/epyc_7662) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7662 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7662_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 7663](https://www.precursorintelligence.com/product/amd/epyc_7663) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7663 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7663_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before milanpi_1.0.0.6 - [Epyc 7702](https://www.precursorintelligence.com/product/amd/epyc_7702) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7702 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7702_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 7702p](https://www.precursorintelligence.com/product/amd/epyc_7702p) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7702p Firmware](https://www.precursorintelligence.com/product/amd/epyc_7702p_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 7713](https://www.precursorintelligence.com/product/amd/epyc_7713) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7713 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7713_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before milanpi_1.0.0.6 - [Epyc 7713p](https://www.precursorintelligence.com/product/amd/epyc_7713p) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7713p Firmware](https://www.precursorintelligence.com/product/amd/epyc_7713p_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before milanpi_1.0.0.6 - [Epyc 7742](https://www.precursorintelligence.com/product/amd/epyc_7742) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7742 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7742_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 7763](https://www.precursorintelligence.com/product/amd/epyc_7763) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7763 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7763_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before milanpi_1.0.0.6 - [Epyc 7773x](https://www.precursorintelligence.com/product/amd/epyc_7773x) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7773x Firmware](https://www.precursorintelligence.com/product/amd/epyc_7773x_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before milanpi_1.0.0.6 - [Epyc 7f32](https://www.precursorintelligence.com/product/amd/epyc_7f32) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7f32 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7f32_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 7f52](https://www.precursorintelligence.com/product/amd/epyc_7f52) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7f52 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7f52_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 7f72](https://www.precursorintelligence.com/product/amd/epyc_7f72) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7f72 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7f72_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Epyc 7h12](https://www.precursorintelligence.com/product/amd/epyc_7h12) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Epyc 7h12 Firmware](https://www.precursorintelligence.com/product/amd/epyc_7h12_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before romepi_1.0.0.d - [Ryzen 3 3100](https://www.precursorintelligence.com/product/amd/ryzen_3_3100) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 3 3100 Firmware](https://www.precursorintelligence.com/product/amd/ryzen_3_3100_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen 3 3300x](https://www.precursorintelligence.com/product/amd/ryzen_3_3300x) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 3 3300x Firmware](https://www.precursorintelligence.com/product/amd/ryzen_3_3300x_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen 5 3500](https://www.precursorintelligence.com/product/amd/ryzen_5_3500) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 5 3500 Firmware](https://www.precursorintelligence.com/product/amd/ryzen_5_3500_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen 5 3500x](https://www.precursorintelligence.com/product/amd/ryzen_5_3500x) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 5 3500x Firmware](https://www.precursorintelligence.com/product/amd/ryzen_5_3500x_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen 5 3600](https://www.precursorintelligence.com/product/amd/ryzen_5_3600) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 5 3600 Firmware](https://www.precursorintelligence.com/product/amd/ryzen_5_3600_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen 5 3600x](https://www.precursorintelligence.com/product/amd/ryzen_5_3600x) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 5 3600x Firmware](https://www.precursorintelligence.com/product/amd/ryzen_5_3600x_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen 5 3600xt](https://www.precursorintelligence.com/product/amd/ryzen_5_3600xt) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 5 3600xt Firmware](https://www.precursorintelligence.com/product/amd/ryzen_5_3600xt_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen 5 5500](https://www.precursorintelligence.com/product/amd/ryzen_5_5500) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 5 5500 Firmware](https://www.precursorintelligence.com/product/amd/ryzen_5_5500_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before comboam4_v2_pi_1.2.0.6 - [Ryzen 5 5600](https://www.precursorintelligence.com/product/amd/ryzen_5_5600) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 5 5600 Firmware](https://www.precursorintelligence.com/product/amd/ryzen_5_5600_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before comboam4_v2_pi_1.2.0.6 - [Ryzen 5 5600x](https://www.precursorintelligence.com/product/amd/ryzen_5_5600x) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 5 5600x Firmware](https://www.precursorintelligence.com/product/amd/ryzen_5_5600x_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before comboam4_v2_pi_1.2.0.6 - [Ryzen 7 3700xt](https://www.precursorintelligence.com/product/amd/ryzen_7_3700xt) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 7 3700xt Firmware](https://www.precursorintelligence.com/product/amd/ryzen_7_3700xt_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen 7 3800x](https://www.precursorintelligence.com/product/amd/ryzen_7_3800x) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 7 3800x Firmware](https://www.precursorintelligence.com/product/amd/ryzen_7_3800x_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen 7 3800xt](https://www.precursorintelligence.com/product/amd/ryzen_7_3800xt) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 7 3800xt Firmware](https://www.precursorintelligence.com/product/amd/ryzen_7_3800xt_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen 7 5700x](https://www.precursorintelligence.com/product/amd/ryzen_7_5700x) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 7 5700x Firmware](https://www.precursorintelligence.com/product/amd/ryzen_7_5700x_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before comboam4_v2_pi_1.2.0.6 - [Ryzen 7 5800](https://www.precursorintelligence.com/product/amd/ryzen_7_5800) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 7 5800 Firmware](https://www.precursorintelligence.com/product/amd/ryzen_7_5800_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before comboam4_v2_pi_1.2.0.6 - [Ryzen 7 5800x](https://www.precursorintelligence.com/product/amd/ryzen_7_5800x) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 7 5800x Firmware](https://www.precursorintelligence.com/product/amd/ryzen_7_5800x_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before comboam4_v2_pi_1.2.0.6 - [Ryzen 7 5800x3d](https://www.precursorintelligence.com/product/amd/ryzen_7_5800x3d) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 7 5800x3d Firmware](https://www.precursorintelligence.com/product/amd/ryzen_7_5800x3d_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before comboam4_v2_pi_1.2.0.6 - [Ryzen 9 3900](https://www.precursorintelligence.com/product/amd/ryzen_9_3900) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 9 3900 Firmware](https://www.precursorintelligence.com/product/amd/ryzen_9_3900_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen 9 3900x](https://www.precursorintelligence.com/product/amd/ryzen_9_3900x) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 9 3900x Firmware](https://www.precursorintelligence.com/product/amd/ryzen_9_3900x_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen 9 3950x](https://www.precursorintelligence.com/product/amd/ryzen_9_3950x) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 9 3950x Firmware](https://www.precursorintelligence.com/product/amd/ryzen_9_3950x_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen 9 3950xt](https://www.precursorintelligence.com/product/amd/ryzen_9_3950xt) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 9 3950xt Firmware](https://www.precursorintelligence.com/product/amd/ryzen_9_3950xt_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen 9 5900](https://www.precursorintelligence.com/product/amd/ryzen_9_5900) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 9 5900 Firmware](https://www.precursorintelligence.com/product/amd/ryzen_9_5900_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before comboam4_v2_pi_1.2.0.6 - [Ryzen 9 5900x](https://www.precursorintelligence.com/product/amd/ryzen_9_5900x) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 9 5900x Firmware](https://www.precursorintelligence.com/product/amd/ryzen_9_5900x_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before comboam4_v2_pi_1.2.0.6 - [Ryzen 9 5950x](https://www.precursorintelligence.com/product/amd/ryzen_9_5950x) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen 9 5950x Firmware](https://www.precursorintelligence.com/product/amd/ryzen_9_5950x_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): before comboam4_v2_pi_1.2.0.6 - [Ryzen Threadripper 3960x](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_3960x) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen Threadripper 3960x Firmware](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_3960x_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen Threadripper 3970x](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_3970x) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen Threadripper 3970x Firmware](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_3970x_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen Threadripper 3990x](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_3990x) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen Threadripper 3990x Firmware](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_3990x_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen Threadripper Pro 3945wx](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_pro_3945wx) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen Threadripper Pro 3945wx Firmware](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_pro_3945wx_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen Threadripper Pro 3955wx](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_pro_3955wx) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen Threadripper Pro 3955wx Firmware](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_pro_3955wx_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen Threadripper Pro 3975wx](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_pro_3975wx) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen Threadripper Pro 3975wx Firmware](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_pro_3975wx_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen Threadripper Pro 3995wx](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_pro_3995wx) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen Threadripper Pro 3995wx Firmware](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_pro_3995wx_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen Threadripper Pro 5945wx](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_pro_5945wx) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen Threadripper Pro 5945wx Firmware](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_pro_5945wx_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen Threadripper Pro 5955wx](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_pro_5955wx) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen Threadripper Pro 5955wx Firmware](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_pro_5955wx_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen Threadripper Pro 5965wx](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_pro_5965wx) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen Threadripper Pro 5965wx Firmware](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_pro_5965wx_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen Threadripper Pro 5975wx](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_pro_5975wx) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen Threadripper Pro 5975wx Firmware](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_pro_5975wx_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified - [Ryzen Threadripper Pro 5995wx](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_pro_5995wx) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Hardware): version not specified - [Ryzen Threadripper Pro 5995wx Firmware](https://www.precursorintelligence.com/product/amd/ryzen_threadripper_pro_5995wx_firmware) by [Amd](https://www.precursorintelligence.com/vendors/amd) (Operating system): version not specified ## How do I fix CVE-2021-26356? 1. **Check whether you run it.** Compare your versions with the affected products above. Not sure what you run? Precursor Intelligence can work it out from your public website, or you can pick it from a list. 2. **Apply the vendor’s fix.** Install the update named in the vendor’s advisory. We’ve put the advisories and patch notes first in the list. 3. **If you can’t patch today.** Follow any mitigation the vendor publishes, and limit who can reach the affected system from the internet until the update is in. 4. **Keep an eye on it.** Track the product and we tell you as soon as we spot this flaw on the list of exploited flaws, or a jump in its exploit likelihood. ### References - [amd.com](https://www.amd.com/en/corporate/product-security/bulletin/AMD-SB-3001) (Vendor advisory) - [amd.com](https://www.amd.com/en/corporate/product-security/bulletin/AMD-SB-4001) (Vendor advisory) ## Questions ### What is CVE-2021-26356? CVE-2021-26356 is a high-severity flaw in Epyc 7001 Firmware from Amd, published on 9 May 2023. It can be attacked from anywhere on the internet without logging in, and nobody has to click anything. If it works, the attacker can read data and change data. ### How serious is CVE-2021-26356? It scores 7.4 out of 10 on the CVSS severity scale, which is high. Our risk score for CVE-2021-26356 is 47 out of 100, which is Medium. Its action is "Plan remediation". No sign of exploitation and a low forecast. Patch it in your normal update cycle. ### Is CVE-2021-26356 being exploited? It is not on the list of flaws known to be exploited today. The latest forecast puts the chance of it being used in the next 30 days at 0.4%. That can change at any time, which is why we keep watching. ### Which versions does CVE-2021-26356 affect? For Epyc 7001 Firmware from Amd: before naplespi_1.0.0.h. The record lists 196 products in all, each with its versions, under "Who is affected" on this page. ### How do I fix CVE-2021-26356? Install the update the vendor names in its advisory, linked first under "How do I fix" on this page. If you can't patch today, follow the vendor's mitigation and limit who can reach the affected system from the internet. ## Does CVE-2021-26356 affect you? Precursor Intelligence keeps checking for you: - **Tell us what you run.** Pick your software from a list, or let us work it out from your website. - **We match it to every flaw.** Over 400,000 published flaws, checked against your list. - **Ranked by real-world risk.** Every flaw gets a 0 to 100 risk score, kept up to date, led by evidence criminals are using it. - **Told as soon as we know.** An alert by email, in the app or by webhook to your own tools. Start free (no card, nothing to install): https://www.precursorintelligence.com/register Book a demo: https://www.precursorintelligence.com/contact