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.

Published: 2023-05-09 Last update: 2025-01-28 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-26356 is rated Moderate Risk (40.7/100): CVSS High severity, with low exploitation likelihood (EPSS 0.40%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-26356

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.26% 0.40% +0.14%
2 2026-05-27 0.17% 0.26% +0.09%
3 2026-02-01 — 0.17% —

Full EPSS history (12 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-26356

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.4 3.1 HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 5.2 [email protected]
7.4 3.1 HIGH
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.2 5.2 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2021-26356

Affected software / configurations for CVE-2021-26356

Vendor Product Version Raw CPE
amd epyc_7001_firmware < naplespi_1.0.0.h cpe:2.3:o:amd:epyc_7001_firmware:*:*:*:*:*:*:*:*
amd epyc_7251_firmware < naplespi_1.0.0.h cpe:2.3:o:amd:epyc_7251_firmware:*:*:*:*:*:*:*:*
amd epyc_7261_firmware < naplespi_1.0.0.h cpe:2.3:o:amd:epyc_7261_firmware:*:*:*:*:*:*:*:*
amd epyc_7281_firmware < naplespi_1.0.0.h cpe:2.3:o:amd:epyc_7281_firmware:*:*:*:*:*:*:*:*
amd epyc_7301_firmware < naplespi_1.0.0.h cpe:2.3:o:amd:epyc_7301_firmware:*:*:*:*:*:*:*:*
amd epyc_7351_firmware < naplespi_1.0.0.h cpe:2.3:o:amd:epyc_7351_firmware:*:*:*:*:*:*:*:*
amd epyc_7351p_firmware < naplespi_1.0.0.h cpe:2.3:o:amd:epyc_7351p_firmware:*:*:*:*:*:*:*:*
amd epyc_7371_firmware < naplespi_1.0.0.h cpe:2.3:o:amd:epyc_7371_firmware:*:*:*:*:*:*:*:*
amd epyc_7401_firmware < naplespi_1.0.0.h cpe:2.3:o:amd:epyc_7401_firmware:*:*:*:*:*:*:*:*
amd epyc_7401p_firmware < naplespi_1.0.0.h cpe:2.3:o:amd:epyc_7401p_firmware:*:*:*:*:*:*:*:*
amd epyc_7451_firmware < naplespi_1.0.0.h cpe:2.3:o:amd:epyc_7451_firmware:*:*:*:*:*:*:*:*
amd epyc_7501_firmware < naplespi_1.0.0.h cpe:2.3:o:amd:epyc_7501_firmware:*:*:*:*:*:*:*:*
amd epyc_7551_firmware < naplespi_1.0.0.h cpe:2.3:o:amd:epyc_7551_firmware:*:*:*:*:*:*:*:*
amd epyc_7551p_firmware < naplespi_1.0.0.h cpe:2.3:o:amd:epyc_7551p_firmware:*:*:*:*:*:*:*:*
amd epyc_7601_firmware < naplespi_1.0.0.h cpe:2.3:o:amd:epyc_7601_firmware:*:*:*:*:*:*:*:*
amd epyc_7002_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7002_firmware:*:*:*:*:*:*:*:*
amd epyc_7232p_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7232p_firmware:*:*:*:*:*:*:*:*
amd epyc_7252_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7252_firmware:*:*:*:*:*:*:*:*
amd epyc_7262_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7262_firmware:*:*:*:*:*:*:*:*
amd epyc_7272_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7272_firmware:*:*:*:*:*:*:*:*
amd epyc_7282_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7282_firmware:*:*:*:*:*:*:*:*
amd epyc_7302_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7302_firmware:*:*:*:*:*:*:*:*
amd epyc_7302p_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7302p_firmware:*:*:*:*:*:*:*:*
amd epyc_7352_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7352_firmware:*:*:*:*:*:*:*:*
amd epyc_7402_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7402_firmware:*:*:*:*:*:*:*:*
amd epyc_7402p_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7402p_firmware:*:*:*:*:*:*:*:*
amd epyc_7452_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7452_firmware:*:*:*:*:*:*:*:*
amd epyc_7502_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7502_firmware:*:*:*:*:*:*:*:*
amd epyc_7532_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7532_firmware:*:*:*:*:*:*:*:*
amd epyc_7542_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7542_firmware:*:*:*:*:*:*:*:*
amd epyc_7552_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7552_firmware:*:*:*:*:*:*:*:*
amd epyc_7642_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7642_firmware:*:*:*:*:*:*:*:*
amd epyc_7662_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7662_firmware:*:*:*:*:*:*:*:*
amd epyc_7702_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7702_firmware:*:*:*:*:*:*:*:*
amd epyc_7702p_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7702p_firmware:*:*:*:*:*:*:*:*
amd epyc_7f32_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7f32_firmware:*:*:*:*:*:*:*:*
amd epyc_7f52_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7f52_firmware:*:*:*:*:*:*:*:*
amd epyc_7f72_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7f72_firmware:*:*:*:*:*:*:*:*
amd epyc_7h12_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7h12_firmware:*:*:*:*:*:*:*:*
amd epyc_7742_firmware < romepi_1.0.0.d cpe:2.3:o:amd:epyc_7742_firmware:*:*:*:*:*:*:*:*
amd epyc_7773x_firmware < milanpi_1.0.0.6 cpe:2.3:o:amd:epyc_7773x_firmware:*:*:*:*:*:*:*:*
amd epyc_7763_firmware < milanpi_1.0.0.6 cpe:2.3:o:amd:epyc_7763_firmware:*:*:*:*:*:*:*:*
amd epyc_7713p_firmware < milanpi_1.0.0.6 cpe:2.3:o:amd:epyc_7713p_firmware:*:*:*:*:*:*:*:*
amd epyc_7713_firmware < milanpi_1.0.0.6 cpe:2.3:o:amd:epyc_7713_firmware:*:*:*:*:*:*:*:*
amd epyc_7663_firmware < milanpi_1.0.0.6 cpe:2.3:o:amd:epyc_7663_firmware:*:*:*:*:*:*:*:*
amd epyc_7643_firmware < milanpi_1.0.0.6 cpe:2.3:o:amd:epyc_7643_firmware:*:*:*:*:*:*:*:*
amd epyc_75f3_firmware < milanpi_1.0.0.6 cpe:2.3:o:amd:epyc_75f3_firmware:*:*:*:*:*:*:*:*
amd epyc_7573x_firmware < milanpi_1.0.0.6 cpe:2.3:o:amd:epyc_7573x_firmware:*:*:*:*:*:*:*:*
amd epyc_7543p_firmware < milanpi_1.0.0.6 cpe:2.3:o:amd:epyc_7543p_firmware:*:*:*:*:*:*:*:*
amd epyc_7543_firmware < milanpi_1.0.0.6 cpe:2.3:o:amd:epyc_7543_firmware:*:*:*:*:*:*:*:*
amd epyc_7513_firmware < milanpi_1.0.0.6 cpe:2.3:o:amd:epyc_7513_firmware:*:*:*:*:*:*:*:*
amd epyc_74f3_firmware < milanpi_1.0.0.6 cpe:2.3:o:amd:epyc_74f3_firmware:*:*:*:*:*:*:*:*
amd epyc_7473x_firmware < milanpi_1.0.0.6 cpe:2.3:o:amd:epyc_7473x_firmware:*:*:*:*:*:*:*:*
amd epyc_7443p_firmware < milanpi_1.0.0.6 cpe:2.3:o:amd:epyc_7443p_firmware:*:*:*:*:*:*:*:*
amd epyc_7443_firmware < milanpi_1.0.0.6 cpe:2.3:o:amd:epyc_7443_firmware:*:*:*:*:*:*:*:*
amd epyc_7453_firmware < milanpi_1.0.0.6 cpe:2.3:o:amd:epyc_7453_firmware:*:*:*:*:*:*:*:*
amd epyc_7413_firmware < milanpi_1.0.0.6 cpe:2.3:o:amd:epyc_7413_firmware:*:*:*:*:*:*:*:*
amd epyc_7373x_firmware < milanpi_1.0.0.6 cpe:2.3:o:amd:epyc_7373x_firmware:*:*:*:*:*:*:*:*
amd epyc_7313_firmware < milanpi_1.0.0.6 cpe:2.3:o:amd:epyc_7313_firmware:*:*:*:*:*:*:*:*
amd epyc_7313p_firmware < milanpi_1.0.0.6 cpe:2.3:o:amd:epyc_7313p_firmware:*:*:*:*:*:*:*:*
amd epyc_7343_firmware < milanpi_1.0.0.6 cpe:2.3:o:amd:epyc_7343_firmware:*:*:*:*:*:*:*:*
amd epyc_72f3_firmware < milanpi_1.0.0.6 cpe:2.3:o:amd:epyc_72f3_firmware:*:*:*:*:*:*:*:*
amd ryzen_9_3950x_firmware — cpe:2.3:o:amd:ryzen_9_3950x_firmware:-:*:*:*:*:*:*:*
amd ryzen_9_3950xt_firmware — cpe:2.3:o:amd:ryzen_9_3950xt_firmware:-:*:*:*:*:*:*:*
amd ryzen_9_3900_firmware — cpe:2.3:o:amd:ryzen_9_3900_firmware:-:*:*:*:*:*:*:*
amd ryzen_9_3900x_firmware — cpe:2.3:o:amd:ryzen_9_3900x_firmware:-:*:*:*:*:*:*:*
amd ryzen_7_3800x_firmware — cpe:2.3:o:amd:ryzen_7_3800x_firmware:-:*:*:*:*:*:*:*
amd ryzen_7_3800xt_firmware — cpe:2.3:o:amd:ryzen_7_3800xt_firmware:-:*:*:*:*:*:*:*
amd ryzen_7_3700xt_firmware — cpe:2.3:o:amd:ryzen_7_3700xt_firmware:-:*:*:*:*:*:*:*
amd ryzen_5_3600x_firmware — cpe:2.3:o:amd:ryzen_5_3600x_firmware:-:*:*:*:*:*:*:*
amd ryzen_5_3600xt_firmware — cpe:2.3:o:amd:ryzen_5_3600xt_firmware:-:*:*:*:*:*:*:*
amd ryzen_5_3600_firmware — cpe:2.3:o:amd:ryzen_5_3600_firmware:-:*:*:*:*:*:*:*
amd ryzen_5_3500x_firmware — cpe:2.3:o:amd:ryzen_5_3500x_firmware:-:*:*:*:*:*:*:*
amd ryzen_5_3500_firmware — cpe:2.3:o:amd:ryzen_5_3500_firmware:-:*:*:*:*:*:*:*
amd ryzen_3_3300x_firmware — cpe:2.3:o:amd:ryzen_3_3300x_firmware:-:*:*:*:*:*:*:*
amd ryzen_3_3100_firmware — cpe:2.3:o:amd:ryzen_3_3100_firmware:-:*:*:*:*:*:*:*
amd ryzen_9_5950x_firmware < comboam4_v2_pi_1.2.0.6 cpe:2.3:o:amd:ryzen_9_5950x_firmware:*:*:*:*:*:*:*:*
amd ryzen_9_5900x_firmware < comboam4_v2_pi_1.2.0.6 cpe:2.3:o:amd:ryzen_9_5900x_firmware:*:*:*:*:*:*:*:*
amd ryzen_9_5900_firmware < comboam4_v2_pi_1.2.0.6 cpe:2.3:o:amd:ryzen_9_5900_firmware:*:*:*:*:*:*:*:*
amd ryzen_7_5800x3d_firmware < comboam4_v2_pi_1.2.0.6 cpe:2.3:o:amd:ryzen_7_5800x3d_firmware:*:*:*:*:*:*:*:*

References for CVE-2021-26356

cvelogic Threat Intelligence