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Epyc 7003 FirmwareOperating system · Amd

CVE-2021-26327

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 validation of guest context in the SNP Firmware could lead to a potential loss of guest confidentiality.

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

This vulnerability exists in AMD's SEV-SNP (Secure Nested Pages) firmware. Insufficient validation of guest context during certain virtualization operations could allow an attacker to potentially access or leak confidential data from a guest virtual machine. This is a firmware-level issue in AMD's confidential computing implementation.

MitigationApply the AMD SEV-SNP firmware update (microcode/firmware patch) provided by AMD for affected processors. Verify that the hypervisor and platform BIOS are also updated to supported versions that include the fix.

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 7003 FirmwareOperating system
Affected:< milanpi-sp3_1.0.0.4
Epyc 72f3 FirmwareOperating system
Affected:< milanpi-sp3_1.0.0.4
Epyc 7313 FirmwareOperating system
Affected:< milanpi-sp3_1.0.0.4
Epyc 7313p FirmwareOperating system
Affected:< milanpi-sp3_1.0.0.4
Epyc 7343 FirmwareOperating system
Affected:< milanpi-sp3_1.0.0.4
Epyc 73f3 FirmwareOperating system
Affected:< milanpi-sp3_1.0.0.4
Epyc 7413 FirmwareOperating system
Affected:< milanpi-sp3_1.0.0.4
Epyc 7443 FirmwareOperating system
Affected:< milanpi-sp3_1.0.0.4

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
High
Integrity
None
Availability
None

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

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 -E "(Model|Version)"' or check /proc/cpuinfo for the CPU model name
    Affected if The processor is not one of the listed affected models (Epyc 72f3, 7313, 7313p, 7343, 73f3, 7413, 7443, or 7003 series)
  2. Verify SEV-SNP is enabled in the system
    Check the hypervisor or BIOS settings for SEV-SNP (Secure Nested Pages) support. On Linux, check 'cat /sys/module/kvm_amd/parameters/sev_snp' or consult hypervisor documentation (e.g., qemu, ESXi)
    Affected if SEV-SNP is not enabled or not available on the system (the vulnerability only applies when SEV-SNP is active)
  3. Retrieve the SEV-SNP firmware version
    On the host, run 'dmesg | grep -i sev' or check 'cat /sys/firmware/efi/vars/SEV-*' for firmware version strings. Consult AMD provisioning tools or hypervisor-specific commands to query the current SEV-SNP firmware build
    Affected if The firmware version is below milanpi-sp3_1.0.0.4 (the version string contains a lower version number or the string is not found)
  4. Confirm the hypervisor and BIOS are using supported versions
    Check the hypervisor version (e.g., 'qemu-system-x86_64 --version' or hypervisor-specific command) and BIOS/UEFI version via 'dmidecode -t bios'
    Affected if The hypervisor or BIOS has not been updated to versions that include the SEV-SNP fix (check with AMD or hypervisor vendor documentation)

A system is affected if it runs an AMD Epyc 7003 series processor (72f3, 7313, 7313p, 7343, 73f3, 7413, 7443) with SEV-SNP enabled and the SEV-SNP firmware version is below milanpi-sp3_1.0.0.4.

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 the AMD SEV-SNP firmware update (microcode/firmware patch) provided by AMD for affected processors. Verify that the hypervisor and platform BIOS are also updated to supported versions that include the fix.

Recommended fix High confidence

milanpi-sp3_1.0.0.4

  1. Obtain the firmware update from AMD's official support website or contact AMD directly for the milanpi-sp3_1.0.0.4 firmware version
  2. Verify the current firmware version on affected Epyc processors using the system's BIOS/UEFI interface or BMC/IPMI tools
  3. Apply the firmware update following AMD's standard firmware update procedure, typically via the BMC web interface, IPMI, or AMD's firmware update utility
  4. After applying the update, verify that the system boots normally and confirm the new firmware version is milanpi-sp3_1.0.0.4 or later
  5. Test that SEV-SNP functionality is operating correctly post-update
Caveat Firmware updates may require system downtime and carry some risk; ensure proper backups and a tested rollback plan before proceeding

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

Fix this in Epyc 7003 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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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-2021-26327 in production — separate from our analysis above.

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What this is

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What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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  • No spam, self-promotion, credentials, or personal data