dbcve.org
Epyc 7601 FirmwareOperating system · Amd

CVE-2021-26312

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
Failure to flush the Translation Lookaside Buffer (TLB) of the I/O memory management unit (IOMMU) may lead an IO device to write to memory it should not be able to access, resulting in a potential loss of 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

This vulnerability stems from the IOMMU (I/O Memory Management Unit) failing to properly flush its Translation Lookaside Buffer (TLB). The TLB caches virtual-to-physical address translations for I/O devices; when not flushed after changes to memory mappings, an IO device may retain stale translation entries and gain write access to memory regions it should not be able to access, compromising system integrity.

MitigationRemediation requires ensuring proper TLB flush operations are executed whenever IOMMU page tables are modified, typically through kernel or firmware updates that enforce correct invalidation sequences.

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 7601 FirmwareOperating system
Affected:< naplespi-sp3_1.0.0.g
Epyc 7551p FirmwareOperating system
Affected:< naplespi-sp3_1.0.0.g
Epyc 7551 FirmwareOperating system
Affected:< naplespi-sp3_1.0.0.g
Epyc 7501 FirmwareOperating system
Affected:< naplespi-sp3_1.0.0.g
Epyc 7451 FirmwareOperating system
Affected:< naplespi-sp3_1.0.0.g
Epyc 7401 FirmwareOperating system
Affected:< naplespi-sp3_1.0.0.g
Epyc 7371 FirmwareOperating system
Affected:< naplespi-sp3_1.0.0.g
Epyc 7351p FirmwareOperating system
Affected:< naplespi-sp3_1.0.0.g

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
None
Availability
None

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

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 processor model
    Run 'dmidecode -s processor-manufacturer' and 'dmidecode -s processor-version' or check /proc/cpuinfo for the CPU model
    Affected if The CPU is an AMD Epyc 7601, 7551p, 7551, 7501, 7451, 7401, 7371, or 7351p
  2. Check the system firmware version
    Use 'dmidecode -s bios-version' or check the BMC/web interface for the firmware version string
    Affected if The firmware version is less than naplespi-sp3_1.0.0.g (e.g., shows an earlier build or different version string)
  3. Verify IOMMU is enabled
    Check for 'amd_iommu=on' or 'intel_iommu=on' in /proc/cmdline, or run 'dmesg | grep -i iommu' to see if the IOMMU is active
    Affected if IOMMU is enabled and the above CPU/firmware conditions are met (the flaw requires IOMMU to be active to be exploitable)
  4. Confirm IOMMU driver is loaded
    Run 'lsmod | grep -i iommu' or check 'dmesg' for 'AMD-Vi' or 'IOMMU' initialization messages
    Affected if AMD IOMMU (AMD-Vi) driver is loaded and the system uses an affected CPU with older firmware

The system is affected if it runs an AMD Epyc 7601/7551/7501/7451/7401/7371/7351p processor with firmware version below naplespi-sp3_1.0.0.g and has IOMMU 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

Remediation requires ensuring proper TLB flush operations are executed whenever IOMMU page tables are modified, typically through kernel or firmware updates that enforce correct invalidation sequences.

Recommended fix High confidence

naplespi-sp3_1.0.0.g

  1. Identify the current firmware version of the AMD Epyc system by accessing the BMC/BIOS or running the command 'dmidecode' or vendor-specific tools
  2. Download the updated firmware naplespi-sp3_1.0.0.g or later from the AMD support website (www.amd.com) for your specific Epyc model
  3. Apply the firmware update through the BMC web interface, IPMI, or vendor-provided update utility following AMD's firmware update instructions
  4. After updating, verify the firmware version has been successfully applied and matches naplespi-sp3_1.0.0.g or later
  5. Reboot the system to ensure the new IOMMU firmware is fully initialized
Caveat Firmware updates may require system downtime and should be tested in a non-production environment first; ensure backup of existing firmware is available

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

Fix this in Epyc 7601 Firmware Scoped from the published advisory
  • Consultation6.0 h
  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
34.0 hours of engineering $6,000
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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-2021-26312 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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