CVE-2021-26402

Insufficient bounds checking in ASP (AMD Secure Processor) firmware while handling BIOS mailbox commands, may allow an attacker to write partially-controlled data out-of-bounds to SMM or SEV-ES regions which may lead to a potential loss of integrity and availability.

Published: 2023-01-11 Last update: 2025-04-08 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-26402 is rated Low Risk (33/100): CVSS High severity, with low exploitation likelihood (EPSS 0.05%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

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-2021-26402

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 2025-03-17 0.04% 0.05% +0.01%
2 2023-03-07 0.89% 0.04% -0.84%
3 2023-01-11 — 0.89% —

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-26402

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.1 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.2 [email protected]
7.1 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.2 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2021-26402

Affected software / configurations for CVE-2021-26402

Vendor Product Version Raw CPE
amd epyc_7h12_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7h12_firmware:*:*:*:*:*:*:*:*
amd epyc_7f72_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7f72_firmware:*:*:*:*:*:*:*:*
amd epyc_7f52_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7f52_firmware:*:*:*:*:*:*:*:*
amd epyc_7f32_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7f32_firmware:*:*:*:*:*:*:*:*
amd epyc_7742_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7742_firmware:*:*:*:*:*:*:*:*
amd epyc_7702p_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7702p_firmware:*:*:*:*:*:*:*:*
amd epyc_7702_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7702_firmware:*:*:*:*:*:*:*:*
amd epyc_7662_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7662_firmware:*:*:*:*:*:*:*:*
amd epyc_7642_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7642_firmware:*:*:*:*:*:*:*:*
amd epyc_7552_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7552_firmware:*:*:*:*:*:*:*:*
amd epyc_7542_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7542_firmware:*:*:*:*:*:*:*:*
amd epyc_7532_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7532_firmware:*:*:*:*:*:*:*:*
amd epyc_7502p_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7502p_firmware:*:*:*:*:*:*:*:*
amd epyc_7502_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7502_firmware:*:*:*:*:*:*:*:*
amd epyc_7452_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7452_firmware:*:*:*:*:*:*:*:*
amd epyc_7402_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7402_firmware:*:*:*:*:*:*:*:*
amd epyc_7402p_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7402p_firmware:*:*:*:*:*:*:*:*
amd epyc_7352_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7352_firmware:*:*:*:*:*:*:*:*
amd epyc_7302p_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7302p_firmware:*:*:*:*:*:*:*:*
amd epyc_7302_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7302_firmware:*:*:*:*:*:*:*:*
amd epyc_7282_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7282_firmware:*:*:*:*:*:*:*:*
amd epyc_7272_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7272_firmware:*:*:*:*:*:*:*:*
amd epyc_7262_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7262_firmware:*:*:*:*:*:*:*:*
amd epyc_7252_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7252_firmware:*:*:*:*:*:*:*:*
amd epyc_7232p_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7232p_firmware:*:*:*:*:*:*:*:*
amd epyc_7002_firmware < romepi_1.0.0.c cpe:2.3:o:amd:epyc_7002_firmware:*:*:*:*:*:*:*:*
amd epyc_7003_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_7003_firmware:*:*:*:*:*:*:*:*
amd epyc_72f3_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_72f3_firmware:*:*:*:*:*:*:*:*
amd epyc_7313_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_7313_firmware:*:*:*:*:*:*:*:*
amd epyc_7313p_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_7313p_firmware:*:*:*:*:*:*:*:*
amd epyc_7343_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_7343_firmware:*:*:*:*:*:*:*:*
amd epyc_7373x_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_7373x_firmware:*:*:*:*:*:*:*:*
amd epyc_73f3_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_73f3_firmware:*:*:*:*:*:*:*:*
amd epyc_7413_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_7413_firmware:*:*:*:*:*:*:*:*
amd epyc_7443_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_7443_firmware:*:*:*:*:*:*:*:*
amd epyc_7443p_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_7443p_firmware:*:*:*:*:*:*:*:*
amd epyc_7453_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_7453_firmware:*:*:*:*:*:*:*:*
amd epyc_74f3_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_74f3_firmware:*:*:*:*:*:*:*:*
amd epyc_7513_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_7513_firmware:*:*:*:*:*:*:*:*
amd epyc_7543_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_7543_firmware:*:*:*:*:*:*:*:*
amd epyc_7543p_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_7543p_firmware:*:*:*:*:*:*:*:*
amd epyc_7573x_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_7573x_firmware:*:*:*:*:*:*:*:*
amd epyc_75f3_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_75f3_firmware:*:*:*:*:*:*:*:*
amd epyc_7643_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_7643_firmware:*:*:*:*:*:*:*:*
amd epyc_7663_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_7663_firmware:*:*:*:*:*:*:*:*
amd epyc_7713_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_7713_firmware:*:*:*:*:*:*:*:*
amd epyc_7713p_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_7713p_firmware:*:*:*:*:*:*:*:*
amd epyc_7743_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_7743_firmware:*:*:*:*:*:*:*:*
amd epyc_7763_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_7763_firmware:*:*:*:*:*:*:*:*
amd epyc_7773x_firmware < milanpi_1.0.0.4 cpe:2.3:o:amd:epyc_7773x_firmware:*:*:*:*:*:*:*:*

References for CVE-2021-26402

cvelogic Threat Intelligence