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Epyc 7763 FirmwareOperating system · Amd

CVE-2021-26370

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
Improper validation of destination address in SVC_LOAD_FW_IMAGE_BY_INSTANCE and SVC_LOAD_BINARY_BY_ATTRIB in a malicious UApp or ABL may allow an attacker to overwrite arbitrary bootloader memory with SPI ROM contents resulting in a loss of integrity and 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

This is a memory corruption vulnerability in AMD bootloader components (UApp/ABL) where the SVC_LOAD_FW_IMAGE_BY_INSTANCE and SVC_LOAD_BINARY_BY_ATTRIB functions fail to properly validate destination addresses. A malicious UApp or ABL can trigger arbitrary memory writes to the bootloader region using data from SPI ROM, allowing an attacker to overwrite bootloader memory contents.

MitigationApply the vendor-provided firmware update that includes proper destination address validation in the affected bootloader functions. Prioritize systems where untrusted UApps can be loaded or where ABL can be modified.

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 check system inventory to confirm the exact Epyc model number (e.g., 7763, 7713p, 7713, 7663, 7643, 75f3, 7543p, 7543)
    Affected if The processor model matches one of the listed affected models (7763, 7713p, 7713, 7663, 7643, 75f3, 7543p, 7543)
  2. Retrieve the current firmware version
    Run 'dmidecode -s bios-version' or check the BMC/web interface for firmware/BIOS version information. For AMD Epyc Milan, look for a version string containing 'milanpi-sp3'
    Affected if The firmware version cannot be determined or is not visible from the operating system (firmware checks require BMC/host console access)
  3. Compare firmware version against the fixed release
    If a firmware version is visible, compare it to 'milanpi-sp3_1.0.0.4'. Versions lower than 1.0.0.4 (e.g., 1.0.0.3, 0.x.x.x) are within the affected range
    Affected if The installed firmware version is below milanpi-sp3_1.0.0.4 (e.g., milanpi-sp3_1.0.0.3 or earlier)
  4. Verify bootloader component version if accessible
    Access the BMC or host console to inspect bootloader (UApp/ABL) version information. This may require vendor-specific tools or firmware dump utilities
    Affected if The bootloader version cannot be verified externally and the system runs firmware versions prior to the milanpi-sp3_1.0.0.4 release

A system is affected if it uses an AMD Epyc 7000-series Milan processor (7763, 7713p, 7713, 7663, 7643, 75f3, 7543p, or 7543) with bootloader firmware version earlier than 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 vendor-provided firmware update that includes proper destination address validation in the affected bootloader functions. Prioritize systems where untrusted UApps can be loaded or where ABL can be modified.

Recommended fix High confidence

milanpi-sp3_1.0.0.4 (or later)

  1. 1. Identify the exact AMD Epyc processor model (e.g., Epyc 7763, Epyc 7713p, etc.) in the affected system
  2. 2. Visit the AMD support website (www.amd.com) and navigate to the drivers and support section for AMD Epyc 7003 series (Milan) processors
  3. 3. Download the firmware update package labeled 'milanpi-sp3_1.0.0.4' or later for your specific processor model
  4. 4. Apply the firmware update following AMD's standard firmware update procedure, typically through the system's BIOS/UEFI update utility or AMD's dedicated firmware update tools
  5. 5. After the update completes, verify that the firmware version has been updated to milanpi-sp3_1.0.0.4 or newer
Caveat Firmware updates carry minimal risk but should be applied during a planned maintenance window; ensure stable power during the update process

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
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA6.0 h
30.0 hours of engineering $5,120
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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-2021-26370 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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