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Epyc 7763 FirmwareOperating system · Amd

CVE-2021-26332

HIGH · 7.1 CVSS v3.1 Published 2022-05-10
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
73/100
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
Failure to verify SEV-ES TMR is not in MMIO space, SEV-ES FW could result in a potential loss of integrity or availability.

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

AMD SEV-ES (Secure Encrypted Virtualization-Encrypted State) firmware fails to verify that the Trusted Memory Region (TMR) is not located in Memory-Mapped I/O (MMIO) space. This validation failure could allow an attacker to place the TMR in MMIO, potentially leading to loss of integrity or availability of the encrypted VM state.

MitigationApply AMD-provided firmware/microcode updates that add proper validation to ensure the TMR cannot be located in MMIO space. Organizations using SEV-ES should coordinate with their hypervisor/cloud provider to ensure the patched firmware is deployed.

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 7763 FirmwareOperating system
Affected:< milanpi-sp3_1.0.0.4
Epyc 7713p FirmwareOperating system
Affected:< milanpi-sp3_1.0.0.4
Epyc 7713 FirmwareOperating system
Affected:< milanpi-sp3_1.0.0.4
Epyc 7663 FirmwareOperating system
Affected:< milanpi-sp3_1.0.0.4
Epyc 7643 FirmwareOperating system
Affected:< milanpi-sp3_1.0.0.4
Epyc 75f3 FirmwareOperating system
Affected:< milanpi-sp3_1.0.0.4
Epyc 7543p FirmwareOperating system
Affected:< milanpi-sp3_1.0.0.4
Epyc 7543 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
None
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/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' or 'cat /proc/cpuinfo' to identify the processor model. Alternatively, use 'cpuid' or check the hypervisor inventory to confirm the specific Epyc model (7763, 7713p, 7713, 7663, 7643, 75f3, 7543p, or 7543).
    Affected if The processor is one of the listed affected Epyc models and the firmware version is below milanpi-sp3_1.0.0.4.
  2. Check the platform firmware version
    Query the system management interface or BIOS/UEFI for the firmware build string. For cloud environments, retrieve this via the provider API (for example, 'aws ec2 describe-instance-types' or similar). Look for a version string containing 'milanpi-sp3'.
    Affected if The firmware version string contains 'milanpi-sp3' with a version lower than 1.0.0.4.
  3. Verify SEV-ES is enabled in the hypervisor or cloud configuration
    Check the hypervisor configuration or VM launch parameters for SEV-ES encryption settings. In Linux, inspect 'cat /sys/firmware/sev' or equivalent SEV capability files if available. For cloud VMs, review the instance metadata or launch configuration for SEV-ES/SEV encryption flags.
    Affected if SEV-ES is actively enabled for the virtual machine or container workload.
  4. Inspect the Trusted Memory Region (TMR) allocation
    Examine the hypervisor or cloud platform configuration that defines the TMR location. In on-premise environments, review the SEV-ES setup documentation or management interface for the TMR base address. In cloud environments, this may require provider-specific tooling or support access.
    Affected if The TMR is configured to reside in a memory region that falls within MMIO address ranges (typically above the system memory boundary).

The environment is affected if an affected Epyc model runs firmware below milanpi-sp3_1.0.0.4, SEV-ES is enabled, and the TMR is configured in or could be placed into MMIO space.

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 firmware/microcode updates that add proper validation to ensure the TMR cannot be located in MMIO space. Organizations using SEV-ES should coordinate with their hypervisor/cloud provider to ensure the patched firmware is deployed.

Recommended fix High confidence

milanpi-sp3_1.0.0.4 or later

  1. Obtain the firmware update from the AMD website or your system vendor supporting the milanpi-sp3_1.0.0.4 release or later
  2. Apply the firmware update to the AMD Epyc processor following your vendor's standard firmware update procedures
  3. Verify the firmware has been successfully applied and the system boots normally
  4. Confirm SEV-ES is functioning properly with the updated firmware

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

Fix this in Epyc 7763 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,120
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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-2021-26332 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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