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Epyc 7763 FirmwareOperating system · Amd

CVE-2021-26324

HIGH · 7.8 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 →
80/100
Remediation priority · High
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
A bug with the SEV-ES TMR may lead to a potential loss of memory integrity for SNP-active VMs.

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 is in AMD SEV-ES (Encrypted State) and affects VMs using SEV-SNP (Secure Nested Paging). A bug in the Trusted Memory Region (TMR) implementation can compromise memory integrity for SNP-active virtual machines, potentially allowing unauthorized memory modifications.

MitigationApply AMD-provided microcode and BIOS updates; ensure hypervisor (KVM/QEMU) and platform firmware are patched to versions that address SEV-ES/SNP TMR issues; verify VM configuration uses recommended SNP settings.

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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 CPU model
    Run `lscpu | grep 'Model name'` or check `/proc/cpuinfo` to confirm the processor is an AMD Epyc from the affected list (7763, 7713p, 7713, 7663, 7643, 75f3, 7543p, 7543).
    Affected if The CPU is one of the listed AMD Epyc models.
  2. Check the system firmware version
    Run `dmidecode -s bios-version` or check the BMC/BIOS web interface for the firmware build string. Look for a version string containing 'milanpi-sp3' and compare it to '1.0.0.4'.
    Affected if The firmware version is present and lower than milanpi-sp3_1.0.0.4, or the version cannot be determined but the CPU model matches.
  3. Verify SEV-ES is enabled for VMs
    Check hypervisor configuration: for KVM/QEMU, inspect VM XML definition (`virsh dumpxml <vmname>`) for `<loader>` or CPU features containing 'sev-es', or check `/sys/module/kvm_amd/parameters/sev_es_enabled` if accessible on the host.
    Affected if SEV-ES encryption is active for any virtual machine on this host.
  4. Confirm SEV-SNP is active
    On the host, run `cat /sys/module/kvm_amd/parameters/sev_snp` or check VM XML for `<cpuid>` entries containing 'SNP'. In guest VMs, verify by running `cpuid | grep -i snp` or checking SEV-SNP status via `dmesg | grep -i sev`.
    Affected if SEV-SNP (Secure Nested Paging) is enabled and the VM is SNP-active.
  5. Inspect TMR configuration
    Check hypervisor logs and configuration for TMR (Trusted Memory Region) settings. For KVM, examine `/var/log/libvirt/qemu/<vmname>.log` or run `virsh dumpxml` and look for SEV-related memory encryption parameters. The TMR is used for SEV-ES/SNP memory integrity.
    Affected if The hypervisor is configured with SEV-ES/SNP and uses a TMR for the affected VMs.

You are affected if you are running any of the listed AMD Epyc processors with firmware below milanpi-sp3_1.0.0.4 and have virtual machines configured with SEV-ES and SEV-SNP 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 microcode and BIOS updates; ensure hypervisor (KVM/QEMU) and platform firmware are patched to versions that address SEV-ES/SNP TMR issues; verify VM configuration uses recommended SNP settings.

Recommended fix High confidence

milanpi-sp3_1.0.0.4 or later

  1. Identify the exact AMD Epyc processor model(s) in your environment from the affected list (Epyc 7763, 7713p, 7713, 7663, 7643, 75f3, 7543p, 7543)
  2. Access the AMD processor firmware download page at www.amd.com or your server manufacturer's support site
  3. Locate the firmware update for your specific Epyc processor model
  4. Download and apply firmware version milanpi-sp3_1.0.0.4 or later
  5. Verify the firmware update was successfully applied
  6. Reboot the system as required by the firmware update process
  7. Confirm SEV-ES functionality is operational after the update
Caveat Firmware updates may require system downtime; ensure proper VM migration or shutdown procedures are in place for SNP-active VMs before applying update

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

Fix this in Epyc 7763 Firmware Scoped from the published advisory
  • Consultation8.0 h
  • Implementation24.0 h
  • Testing16.0 h
  • Review / QA8.0 h
56.0 hours of engineering $9,760
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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-2021-26324 in production — separate from our analysis above.

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  • Version or environment caveats, and links to real fixes
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