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Epyc 7003 FirmwareOperating system · Amd

CVE-2021-26336

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 bounds checking in System Management Unit (SMU) may cause invalid memory accesses/updates that could result in SMU hang and subsequent failure to service any further requests from other components.

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's System Management Unit (SMU) firmware allows invalid memory accesses and updates, leading to SMU hang and complete failure to service subsequent requests from other system components, effectively causing a denial-of-service condition.

MitigationApply AMD-provided SMU firmware updates (typically delivered via BIOS/UEFI updates) to patch the bounds checking vulnerabilities; verify SMU stability post-update.

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 7002 FirmwareOperating system
Affected:< romepi-sp3_1.0.0.c
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

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
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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 your AMD Epyc processor model
    Run 'dmidecode -t processor' or check system BIOS/UEFI under processor information to determine if you have an Epyc 7003, 7002, 72f3, 7313, 7313p, 7343, 73f3, or 7413 processor
    Affected if The processor model matches one of the affected Epyc models listed in the CVE (7003, 7002, 72f3, 7313, 7313p, 7343, 73f3, or 7413)
  2. Check SMU firmware version via BMC/IPMI
    Use IPMI command 'ipmitool raw' or access BMC web interface to retrieve SMU firmware version. On HP/Dell/Lenovo servers, use their respective management tools (HP iLO, Dell iDRAC, Lenovo XClarity). The SMU firmware version is typically shown in the BIOS/firmware inventory section
    Affected if The SMU firmware version is revealed and can be compared against the vulnerable version thresholds
  3. Check SMU firmware version via system BIOS
    Enter BIOS/UEFI setup during boot and navigate to System Information or Firmware Versions section to locate the SMU firmware version. Some systems display this on the initial boot screen under firmware information
    Affected if The SMU firmware version is displayed and can be compared against the vulnerable version thresholds
  4. Compare installed version to affected thresholds
    Match your processor model and SMU firmware version against the CVE version thresholds: Epyc 7003/72f3/7313/7313p/7343/73f3/7413 require < milanpi-sp3_1.0.0.4; Epyc 7002 requires < romepi-sp3_1.0.0.c. If your version is lower than the threshold, you are affected
    Affected if The installed SMU firmware version is below the fixed version for your specific processor model (milanpi-sp3_1.0.0.4 for 7003/72f3/7313/7313p/7343/73f3/7413, or romepi-sp3_1.0.0.c for 7002)

You are affected if you have an AMD Epyc 7002, 7003, 72f3, 7313, 7313p, 7343, 73f3, or 7413 processor AND your installed SMU firmware version is lower than the fixed version threshold for your specific model.

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 SMU firmware updates (typically delivered via BIOS/UEFI updates) to patch the bounds checking vulnerabilities; verify SMU stability post-update.

Recommended fix High confidence

milanpi-sp3_1.0.0.4 (for Epyc 7003/72f3/7313/7313p/7343/73f3/7413) or romepi-sp3_1.0.0.c (for Epyc 7002)

  1. 1. Identify the exact AMD Epyc processor model (7002, 7003, 72f3, 7313, 7313p, 7343, 73f3, or 7413) in the affected system.
  2. 2. Check the current firmware version of the System Management Unit (SMU) - this is typically viewable via IPMI, BMC web interface, or AMD's platform management tools.
  3. 3. For Epyc 7002 systems: upgrade SMU firmware to version romepi-sp3_1.0.0.c or later.
  4. 4. For Epyc 7003, 72f3, 7313, 7313p, 7343, 73f3, and 7413 systems: upgrade SMU firmware to version milanpi-sp3_1.0.0.4 or later.
  5. 5. Obtain the firmware update utility and firmware binary from AMD's support website (www.amd.com) or through the server OEM's firmware distribution channel.
  6. 6. Apply the firmware update following the OEM's recommended procedure - this usually involves rebooting the server or using a firmware update tool via the BMC/IPMI interface.
  7. 7. After updating, verify the SMU firmware version has been successfully applied and confirm the system is operating normally.
Caveat Firmware updates carry inherent risk and should be tested in a non-production environment first; some updates may require a server reboot which causes downtime

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
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,480
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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-2021-26336 in production — separate from our analysis above.

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  • Version or environment caveats, and links to real fixes
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