CVE-2021-26403

Insufficient checks in SEV may lead to a malicious hypervisor disclosing the launch secret potentially resulting in compromise of VM confidentiality.

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-2021-26403 is rated Low Risk (28.9/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.03%). 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-2021-26403

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 2026-03-13 0.07% 0.03% -0.04%
2 2025-11-21 0.03% 0.07% +0.04%
3 2025-11-18 — 0.03% —

Full EPSS history (6 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-26403

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N 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:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.0 4.0 [email protected]
6.5 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N 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:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.0 4.0 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2021-26403

Affected software / configurations for CVE-2021-26403

Vendor Product Version Raw CPE
amd epyc_7001_firmware < naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7001_firmware:*:*:*:*:*:*:*:*
amd epyc_7251_firmware < naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7251_firmware:*:*:*:*:*:*:*:*
amd epyc_7261_firmware < naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7261_firmware:*:*:*:*:*:*:*:*
amd epyc_7281_firmware < naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7281_firmware:*:*:*:*:*:*:*:*
amd epyc_7301_firmware < naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7301_firmware:*:*:*:*:*:*:*:*
amd epyc_7351_firmware < naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7351_firmware:*:*:*:*:*:*:*:*
amd epyc_7351p_firmware < naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7351p_firmware:*:*:*:*:*:*:*:*
amd epyc_7371_firmware < naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7371_firmware:*:*:*:*:*:*:*:*
amd epyc_7401_firmware < naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7401_firmware:*:*:*:*:*:*:*:*
amd epyc_7401p_firmware < naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7401p_firmware:*:*:*:*:*:*:*:*
amd epyc_7451_firmware < naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7451_firmware:*:*:*:*:*:*:*:*
amd epyc_7501_firmware < naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7501_firmware:*:*:*:*:*:*:*:*
amd epyc_7551_firmware < naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7551_firmware:*:*:*:*:*:*:*:*
amd epyc_7551p_firmware < naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7551p_firmware:*:*:*:*:*:*:*:*
amd epyc_7601_firmware < naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7601_firmware:*:*:*:*:*:*:*:*
amd epyc_7002_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7002_firmware:*:*:*:*:*:*:*:*
amd epyc_7232p_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7232p_firmware:*:*:*:*:*:*:*:*
amd epyc_7252_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7252_firmware:*:*:*:*:*:*:*:*
amd epyc_7262_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7262_firmware:*:*:*:*:*:*:*:*
amd epyc_7272_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7272_firmware:*:*:*:*:*:*:*:*
amd epyc_7282_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7282_firmware:*:*:*:*:*:*:*:*
amd epyc_7302_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7302_firmware:*:*:*:*:*:*:*:*
amd epyc_7302p_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7302p_firmware:*:*:*:*:*:*:*:*
amd epyc_7352_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7352_firmware:*:*:*:*:*:*:*:*
amd epyc_7402_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7402_firmware:*:*:*:*:*:*:*:*
amd epyc_7402p_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7402p_firmware:*:*:*:*:*:*:*:*
amd epyc_7452_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7452_firmware:*:*:*:*:*:*:*:*
amd epyc_7502_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7502_firmware:*:*:*:*:*:*:*:*
amd epyc_7502p_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7502p_firmware:*:*:*:*:*:*:*:*
amd epyc_7532_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7532_firmware:*:*:*:*:*:*:*:*
amd epyc_7542_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7542_firmware:*:*:*:*:*:*:*:*
amd epyc_7552_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7552_firmware:*:*:*:*:*:*:*:*
amd epyc_7642_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7642_firmware:*:*:*:*:*:*:*:*
amd epyc_7662_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7662_firmware:*:*:*:*:*:*:*:*
amd epyc_7702_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7702_firmware:*:*:*:*:*:*:*:*
amd epyc_7702p_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7702p_firmware:*:*:*:*:*:*:*:*
amd epyc_7742_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7742_firmware:*:*:*:*:*:*:*:*
amd epyc_7f32_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7f32_firmware:*:*:*:*:*:*:*:*
amd epyc_7f52_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7f52_firmware:*:*:*:*:*:*:*:*
amd epyc_7f72_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7f72_firmware:*:*:*:*:*:*:*:*
amd epyc_7h12_firmware < romepi_1.0.0.9 cpe:2.3:o:amd:epyc_7h12_firmware:*:*:*:*:*:*:*:*

References for CVE-2021-26403

cvelogic Threat Intelligence