How severe is CVE-2021-26320?

CVE-2021-26320 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-26320 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-26320?

CVE-2021-26320 primarily affects Amd Epyc 7601 Firmware. In total, 57 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-26320?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-26320 published?

CVE-2021-26320 was published on 2021-11-16 and last updated on 2026-06-17.

CVE-2021-26320

CVE-2021-26320 is a medium-severity vulnerability in Amd Epyc 7601 Firmware with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-295.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
CVSS v2: 2.1
EPSS exploit prediction: 0% (8th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-295
Affected product: Amd Epyc 7601 Firmware
Published: 2021-11-16
Last modified: 2026-06-17

Description

Insufficient validation of the AMD SEV Signing Key (ASK) in the SEND_START command in the SEV Firmware may allow a local authenticated attacker to perform a denial of service of the PSP

Frequently asked questions

What is CVE-2021-26320?: Insufficient validation of the AMD SEV Signing Key (ASK) in the SEND_START command in the SEV Firmware may allow a local authenticated attacker to perform a denial of service of the PSP
How severe is CVE-2021-26320?: CVE-2021-26320 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-26320 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (8th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-26320?: CVE-2021-26320 primarily affects Amd Epyc 7601 Firmware. In total, 57 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-26320?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-26320 published?: CVE-2021-26320 was published on 2021-11-16 and last updated on 2026-06-17.

References

https://www.amd.com/en/corporate/product-security/bulletin/amd-sb-1021

Affected products (57)

cpe:2.3:o:amd:epyc_7601_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7551p_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7551_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7501_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7451_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7401_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7371_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7351p_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7351_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7301_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7281_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7261_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7251_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7f72_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7f52_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7f32_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7h12_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7742_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7702_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7702p_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7662_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7642_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7552_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7542_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7532_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7502_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7502p_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7452_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7402_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7402p_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7352_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7302_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7302p_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7282_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7272_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7262_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7252_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7232p_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7763_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:amd:epyc_7713p_firmware:*:*:*:*:*:*:*:*

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