dbcve.org
Epyc 7601 FirmwareOperating system · Amd

CVE-2021-26321

MEDIUM · 5.5 CVSS v3.1 Published 2021-11-16
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
57/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Insufficient ID command validation in the SEV Firmware may allow a local authenticated attacker to perform a denial of service of the PSP.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

Insufficient ID command validation in AMD SEV (Secure Encrypted Virtualization) Firmware allows a local authenticated attacker to send malformed ID commands to the Platform Security Processor (PSP), causing a denial of service condition. The PSP is AMD's dedicated security processor, and its compromise affects the entire system's security foundation.

MitigationApply AMD-provided SEV firmware updates that address command validation. Restrict local administrative access to systems with SEV-enabled virtual machines to limit attack surface.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Epyc 7601 FirmwareOperating system
Affected:< naplespi-sp3_1.0.0.g
Epyc 7551p FirmwareOperating system
Affected:< naplespi-sp3_1.0.0.g
Epyc 7551 FirmwareOperating system
Affected:< naplespi-sp3_1.0.0.g
Epyc 7501 FirmwareOperating system
Affected:< naplespi-sp3_1.0.0.g
Epyc 7451 FirmwareOperating system
Affected:< naplespi-sp3_1.0.0.g
Epyc 7401 FirmwareOperating system
Affected:< naplespi-sp3_1.0.0.g
Epyc 7371 FirmwareOperating system
Affected:< naplespi-sp3_1.0.0.g
Epyc 7351p FirmwareOperating system
Affected:< naplespi-sp3_1.0.0.g

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the AMD Epyc processor model
    Run 'dmidecode -t processor | grep -i "AMD Epyc"' or check /proc/cpuinfo for the processor name
    Affected if The processor model matches any of the following: 7601, 7551p, 7551, 7501, 7451, 7401, 7371, or 7351p
  2. Check SEV firmware version
    Query the PSP firmware version via 'cat /sys/firmware/amd/naplespi/sp3_version' or use the AMD PSP driver debug interface if available
    Affected if The firmware version is present and less than naplespi-sp3_1.0.0.g, or the version file is missing/unreadable on an affected CPU
  3. Verify SEV is enabled in the system
    Check for SEV capability with 'kvm-sev-status' (if available) or examine BIOS/UEFI settings for SEV or SME/SEV configuration options
    Affected if SEV is enabled and the processor is an affected model with vulnerable firmware
  4. Confirm PSP responsiveness
    Monitor system logs for PSP-related errors or check /dev/amd-psp for device availability and any error indicators
    Affected if The PSP shows irregular behavior or is unreachable after any ID command operations on affected hardware

The system is affected if it runs any of the listed AMD Epyc models (7601, 7551p, 7551, 7501, 7451, 7401, 7371, 7351p) with SEV firmware version earlier than naplespi-sp3_1.0.0.g and has SEV functionality enabled.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply AMD-provided SEV firmware updates that address command validation. Restrict local administrative access to systems with SEV-enabled virtual machines to limit attack surface.

Recommended fix High confidence

naplespi-sp3_1.0.0.g

  1. Identify the current SEV firmware version on the affected AMD Epyc processor by querying the PSP or checking system firmware logs
  2. Download the naplespi-sp3_1.0.0.g or later firmware update from the AMD support website (www.amd.com) for your specific Epyc model
  3. Apply the firmware update using the AMD-provided flashing utility or through the system BIOS/UEFI firmware update mechanism
  4. Verify the firmware update was successful by confirming the new version matches naplespi-sp3_1.0.0.g or later
  5. Reboot the system to ensure the updated SEV firmware is fully initialized
Caveat Firmware updates carry inherent risk; ensure backups are in place and follow AMD's recommended update procedure for your specific platform

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Epyc 7601 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-26321 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data