NVD / CVE Program· CNA AMD

CVE-2021-26323: Failure to validate SEV Commands while SNP is active may result in a potential impact to memory integrity.

Noroxi assessment

Priority: Monitor (action score 31/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.24% (FIRST EPSS).
Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
According to the record, no fixed version is available yet.

Low priority for now. Update when a fix is released; follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

HighCVSS 7.8 · v3.1—No exploit No fix recorded

Published: Nov 16, 2021
Updated: Jun 16, 2026
EPSS: 0.2% · 15th percentile
CWE: CWE-20

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 31 / 40 · 7.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.2%

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
amd	epyc 7232p firmware	cpe:2.3:o:amd:epyc_7232p_firmware
amd	epyc 7232p	cpe:2.3:h:amd:epyc_7232p
amd	epyc 7763 firmware	cpe:2.3:o:amd:epyc_7763_firmware
amd	epyc 7763	cpe:2.3:h:amd:epyc_7763
amd	epyc 7713p firmware	cpe:2.3:o:amd:epyc_7713p_firmware
amd	epyc 7713p	cpe:2.3:h:amd:epyc_7713p
amd	epyc 7713 firmware	cpe:2.3:o:amd:epyc_7713_firmware
amd	epyc 7713	cpe:2.3:h:amd:epyc_7713
amd	epyc 7663 firmware	cpe:2.3:o:amd:epyc_7663_firmware
amd	epyc 7663	cpe:2.3:h:amd:epyc_7663
amd	epyc 7643 firmware	cpe:2.3:o:amd:epyc_7643_firmware
amd	epyc 7643	cpe:2.3:h:amd:epyc_7643

and 28 more

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

amd epyc 7232p firmwarebefore romepi-sp3_1.0.0.c
amd epyc 72f3 firmwarebefore milanpi-sp3_1.0.0.4
amd epyc 7313 firmwarebefore milanpi-sp3_1.0.0.4
amd epyc 7313p firmwarebefore milanpi-sp3_1.0.0.4
amd epyc 7343 firmwarebefore milanpi-sp3_1.0.0.4
amd epyc 73f3 firmwarebefore milanpi-sp3_1.0.0.4
amd epyc 7413 firmwarebefore milanpi-sp3_1.0.0.4
amd epyc 7443 firmwarebefore milanpi-sp3_1.0.0.4
amd epyc 7443p firmwarebefore milanpi-sp3_1.0.0.4
amd epyc 7453 firmwarebefore milanpi-sp3_1.0.0.4
amd epyc 74f3 firmwarebefore milanpi-sp3_1.0.0.4
amd epyc 7513 firmwarebefore milanpi-sp3_1.0.0.4
amd epyc 7543 firmwarebefore milanpi-sp3_1.0.0.4
amd epyc 7543p firmwarebefore milanpi-sp3_1.0.0.4
amd epyc 75f3 firmwarebefore milanpi-sp3_1.0.0.4
amd epyc 7643 firmwarebefore milanpi-sp3_1.0.0.4
amd epyc 7663 firmwarebefore milanpi-sp3_1.0.0.4
amd epyc 7713 firmwarebefore milanpi-sp3_1.0.0.4
amd epyc 7713p firmwarebefore milanpi-sp3_1.0.0.4
amd epyc 7763 firmwarebefore milanpi-sp3_1.0.0.4

Versions reported by the vendor

Affected version ranges reported by the assigning authority (AMD). Independent of NVD's CPE analysis and usually ahead of it.

AMD 3rd Gen AMD EPYC™
- unspecified and later · before MilanPI-SP3_1.0.0.4affected

Same product

amd: all records

Other highest-scoring records for the same primary product.

CVE-2021-26326Failure to validate VM_HSAVE_PA during SNP_INIT may result in a loss of memory integrity.
31Monitor
CVE-2023-20533Insufficient DRAM address validation in System Management Unit (SMU) may allow an attacker to read/write from/to an invalid DRAM address, po
30Monitor
CVE-2021-26406Insufficient validation in parsing Owner's Certificate Authority (OCA) certificates in SEV (AMD Secure Encrypted Virtualization) and SEV-ES
30Monitor

Published before and after this one in the same product

Later →CVE-2021-26325Nov 16, 2021 · Insufficient input validation in the SNP_GUEST_REQUEST command may lead to a potential data abort error and a denial of service.
22Monitor
Later →CVE-2021-26350May 11, 2022 · A TOCTOU race condition in SMU may allow for the caller to obtain and manipulate the address of a message port register which may result in
18Monitor
Later →CVE-2021-26364May 11, 2022 · Insufficient bounds checking in an SMU mailbox register could allow an attacker to potentially read outside of the SRAM address range which
22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Someone with local access to the system can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Local
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-20 · Improper Input Validation

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

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

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records