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Milanpi FirmwareOperating system · Amd

CVE-2021-26409

HIGH · 7.8 CVSS v3.1 Published 2023-01-11
Fix available
A fix is available. Upgrade to 1.0.0.3 or later.
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
Insufficient bounds checking in SEV-ES may allow an attacker to corrupt Reverse Map table (RMP) memory, potentially resulting in a loss of SNP (Secure Nested Paging) memory integrity.

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 bounds checking in AMD SEV-ES (Secure Encrypted Virtualization-Encrypted State) allows an attacker to corrupt Reverse Map Table (RMP) memory. The RMP is a critical data structure in AMD's memory encryption architecture that maintains mappings between physical and encrypted memory. This corruption can compromise SNP (Secure Nested Paging) memory integrity, potentially allowing unauthorized access to protected VM data.

MitigationApply AMD-provided firmware/hypervisor updates that address the bounds checking vulnerability in SEV-ES. Verify that all hosts running SEV or SEV-SNP enabled VMs have updated AMD firmware and that the hypervisor (e.g., SEV-capable KVM) is patched to the latest version.

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
Milanpi FirmwareOperating system
Affected:< 1.0.0.3

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 AMD processor model
    Run 'cat /proc/cpuinfo' and look for 'GenuineIntel' replaced with AuthenticAMD, then check the model name (e.g., EPYC 7xxx series) or use 'dmidecode -t processor | grep -i 'family'' to determine if this is a Milanpi processor
    Affected if The system does not have an AMD Milan (or later) processor - this vulnerability only affects that specific platform
  2. Verify SEV-ES or SEV-SNP is enabled
    Check the hypervisor or BIOS settings. For Linux hosts, run 'cat /sys/module/kvm_amd/parameters/sev_es' or check if 'sev' or 'sev-snp' appears in hypervisor capabilities (e.g., 'virsh capabilities' for KVM)
    Affected if SEV-ES is not enabled on the system - the vulnerability only applies when this feature is active
  3. Obtain the AMD firmware version
    On AMD SEV-enabled systems, the firmware version is typically exposed via hypervisor interfaces. For Linux KVM, check 'cat /sys/firmware/acpi/tables/SEV' or use 'amdpu -i' if available. Alternatively, check the hypervisor's SEV capability output for version information
    Affected if The firmware version cannot be determined or is lower than 1.0.0.3 on an AMD Milanpi platform with SEV-ES enabled
  4. Compare installed firmware version against affected range
    Review the firmware version obtained from the previous step and compare it to the vulnerable range: all versions less than 1.0.0.3 on AMD Milanpi processors
    Affected if The installed firmware version is below 1.0.0.3 (e.g., 1.0.0.0, 1.0.0.1, 1.0.0.2) and the system uses AMD Milanpi with SEV-ES active

A system is affected if it runs on AMD Milanpi hardware with SEV-ES or SEV-SNP enabled and has firmware version earlier than 1.0.0.3.

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
Upgrade available Upgrade to 1.0.0.3 or later
Fixed in 1.0.0.3
Interim mitigation

Apply AMD-provided firmware/hypervisor updates that address the bounds checking vulnerability in SEV-ES. Verify that all hosts running SEV or SEV-SNP enabled VMs have updated AMD firmware and that the hypervisor (e.g., SEV-capable KVM) is patched to the latest version.

Recommended fix High confidence

Milanpi Firmware version 1.0.0.3

  1. Identify the current Milanpi Firmware version running on the affected AMD EPYC system
  2. Download the latest Milanpi Firmware version 1.0.0.3 or later from the AMD support website (support.amd.com)
  3. Apply the firmware update following AMD's standard firmware update procedure for the specific platform/server model
  4. Verify the firmware version has been successfully updated to 1.0.0.3 or later
  5. Reboot the system as required by the firmware update process
Caveat Firmware updates may require server downtime and should be planned during maintenance windows; ensure proper backup and validation procedures are followed

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

Fix this in Milanpi Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,970
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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-2021-26409 in production — separate from our analysis above.

No notes yet

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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