CVE-2021-26406

Insufficient validation in parsing Owner's Certificate Authority (OCA) certificates in SEV (AMD Secure Encrypted Virtualization) and SEV-ES user application can lead to a host crash potentially resulting in denial of service.

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-2021-26406 is rated Moderate Risk (52.3/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.45%). 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-2021-26406

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 2026-05-31 0.47% 0.45% -0.03%
2 2026-05-24 0.18% 0.47% +0.29%
3 2026-02-01 — 0.18% —

Full EPSS history (10 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-26406

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H 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:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H 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:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2021-26406

Affected software / configurations for CVE-2021-26406

Vendor Product Version Raw CPE
amd epyc_7232p_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7232p_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7252_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7252_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7262_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7262_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7272_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7272_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7282_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7282_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7302_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7302_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7302p_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7302p_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7352_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7352_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7402_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7402_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7402p_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7402p_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7452_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7452_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7502_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7502_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7502p_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7502p_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7532_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7532_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7542_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7542_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7552_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7552_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7642_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7642_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7662_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7662_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7702_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7702_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7702p_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7702p_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7742_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7742_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7f32_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7f32_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7f52_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7f52_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7f72_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7f72_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7h12_firmware romepi_1.0.0.a cpe:2.3:o:amd:epyc_7h12_firmware:romepi_1.0.0.a:*:*:*:*:*:*:*
amd epyc_7251_firmware naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7251_firmware:naplespi_1.0.0.e:*:*:*:*:*:*:*
amd epyc_7261_firmware naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7261_firmware:naplespi_1.0.0.e:*:*:*:*:*:*:*
amd epyc_7281_firmware naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7281_firmware:naplespi_1.0.0.e:*:*:*:*:*:*:*
amd epyc_7301_firmware naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7301_firmware:naplespi_1.0.0.e:*:*:*:*:*:*:*
amd epyc_7351_firmware naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7351_firmware:naplespi_1.0.0.e:*:*:*:*:*:*:*
amd epyc_7351p_firmware naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7351p_firmware:naplespi_1.0.0.e:*:*:*:*:*:*:*
amd epyc_7371_firmware naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7371_firmware:naplespi_1.0.0.e:*:*:*:*:*:*:*
amd epyc_7401_firmware naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7401_firmware:naplespi_1.0.0.e:*:*:*:*:*:*:*
amd epyc_7401p_firmware naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7401p_firmware:naplespi_1.0.0.e:*:*:*:*:*:*:*
amd epyc_7451_firmware naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7451_firmware:naplespi_1.0.0.e:*:*:*:*:*:*:*
amd epyc_7501_firmware naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7501_firmware:naplespi_1.0.0.e:*:*:*:*:*:*:*
amd epyc_7551_firmware naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7551_firmware:naplespi_1.0.0.e:*:*:*:*:*:*:*
amd epyc_7551p_firmware naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7551p_firmware:naplespi_1.0.0.e:*:*:*:*:*:*:*
amd epyc_7571_firmware naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7571_firmware:naplespi_1.0.0.e:*:*:*:*:*:*:*
amd epyc_7601_firmware naplespi_1.0.0.e cpe:2.3:o:amd:epyc_7601_firmware:naplespi_1.0.0.e:*:*:*:*:*:*:*

References for CVE-2021-26406

cvelogic Threat Intelligence