dbcve.org
Epyc 7232p FirmwareOperating system · Amd

CVE-2021-26364

MEDIUM · 5.5 CVSS v3.1 Published 2022-05-11
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 an SMU mailbox register could allow an attacker to potentially read outside of the SRAM address range which could result in an exception handling leading to a potential denial of service.

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 an AMD System Management Unit (SMU) mailbox register allows an attacker to read beyond the allocated SRAM address range, triggering exception handling that causes a denial of service condition.

MitigationApply vendor-provided firmware/BIOS updates from AMD that address the SMU mailbox bounds checking vulnerability; contact the hardware vendor for specific patch availability and deployment guidance.

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 7232p FirmwareOperating system
Affected:< romepi-sp3_1.0.0.d
Epyc 7302p FirmwareOperating system
Affected:< romepi-sp3_1.0.0.d
Epyc 7402p FirmwareOperating system
Affected:< romepi-sp3_1.0.0.d
Epyc 7502p FirmwareOperating system
Affected:< romepi-sp3_1.0.0.d
Epyc 7702p FirmwareOperating system
Affected:< romepi-sp3_1.0.0.d
Epyc 7252 FirmwareOperating system
Affected:< romepi-sp3_1.0.0.d
Epyc 7262 FirmwareOperating system
Affected:< romepi-sp3_1.0.0.d
Epyc 7272 FirmwareOperating system
Affected:< romepi-sp3_1.0.0.d

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 the AMD Epyc processor model
    Run 'dmidecode -t processor' or 'lscpu | grep -i amd' to confirm the installed CPU is one of the affected models: Epyc 7232p, 7302p, 7402p, 7502p, 7702p, 7252, 7262, or 7272
    Affected if The processor is an AMD Epyc model from the affected list
  2. Check the SMU firmware version
    Use 'dmidecode -s bios-version' to retrieve the firmware version string, or use vendor-specific tools such as AMD's PSP/TPM diagnostics or IPMI to query the SMU firmware version. The version string typically appears as 'romepi-sp3_X.X.X.X' or similar
    Affected if The SMU firmware version is earlier than 'romepi-sp3_1.0.0.d'
  3. Verify SMU mailbox functionality is accessible
    Confirm the System Management Unit is active and accessible in the system. On Linux, check for SMU-related entries in /dev or use 'dmesg' to look for SMU initialization messages. The vulnerability requires SMU mailbox register access to be available
    Affected if SMU mailbox interface is present and operational in the system

A system is affected if it runs an AMD Epyc processor from the listed models with SMU firmware version earlier than romepi-sp3_1.0.0.d and the SMU mailbox is accessible

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 vendor-provided firmware/BIOS updates from AMD that address the SMU mailbox bounds checking vulnerability; contact the hardware vendor for specific patch availability and deployment guidance.

Recommended fix High confidence

romepi-sp3_1.0.0.d or later

  1. 1. Identify the current firmware version of the affected AMD Epyc processor by accessing the BMC/BIOS interface or using command-line tools like ipmiutil or dmidecode
  2. 2. Navigate to AMD's official support website (www.amd.com) and locate the firmware download page for your specific Epyc processor model
  3. 3. Download the updated firmware package named 'romepi-sp3_1.0.0.d' or later for your specific Epyc model
  4. 4. Apply the firmware update through the BMC web interface or using BMC firmware update utilities (e.g., ipmiutil, amdfwupd) following AMD's documented update procedure
  5. 5. Verify the firmware version has been successfully updated to romepi-sp3_1.0.0.d or later
  6. 6. Reboot the system as required by the firmware update process
Caveat Firmware updates carry risk of system instability; test in non-production environment first and ensure uninterrupted power during update process

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

Fix this in Epyc 7232p Firmware Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,060
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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-2021-26364 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