dbcve.org
Epyc 7763 FirmwareOperating system · Amd

CVE-2021-26348

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
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 TLB (Translation Lookaside Buffer). When the TLB is not flushed after changes to page tables, an I/O device may retain stale translations that grant access to memory regions it should no longer be able to write to, compromising memory integrity.

MitigationApply vendor-provided BIOS/firmware updates that address the IOMMU TLB flush issue. Verify that IOMMU settings are properly configured and test system stability after applying the 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 7763 FirmwareOperating system
Affected:< milanpi-sp3_1.0.0.7
Epyc 7713p FirmwareOperating system
Affected:< milanpi-sp3_1.0.0.7
Epyc 7713 FirmwareOperating system
Affected:< milanpi-sp3_1.0.0.7
Epyc 7663 FirmwareOperating system
Affected:< milanpi-sp3_1.0.0.7
Epyc 7643 FirmwareOperating system
Affected:< milanpi-sp3_1.0.0.7
Epyc 75f3 FirmwareOperating system
Affected:< milanpi-sp3_1.0.0.7
Epyc 7543p FirmwareOperating system
Affected:< milanpi-sp3_1.0.0.7
Epyc 7543 FirmwareOperating system
Affected:< milanpi-sp3_1.0.0.7

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
None

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/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 CPU model
    Run 'dmidecode -s processor-version' or check /proc/cpuinfo to determine the exact AMD Epyc processor model
    Affected if The CPU model is one of: Epyc 7763, Epyc 7713p, Epyc 7713, Epyc 7663, Epyc 7643, Epyc 75f3, Epyc 7543p, or Epyc 7543
  2. Check firmware version
    Use 'dmidecode -s bios-version' or access the BIOS/UEFI firmware version information via IPMI, BMC, or during boot. Compare against the version string 'milanpi-sp3_1.0.0.7'
    Affected if The firmware version is lower than milanpi-sp3_1.0.0.7
  3. Verify IOMMU is enabled
    Check BIOS/UEFI settings for IOMMU or AMD-Vi configuration, or run 'dmesg | grep -i iommu' to see if IOMMU is active at runtime
    Affected if IOMMU is enabled in the system (the vulnerability only applies when IOMMU is active)

You are affected if you run any of the listed AMD Epyc models with firmware below milanpi-sp3_1.0.0.7 and have IOMMU enabled in your system configuration.

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 BIOS/firmware updates that address the IOMMU TLB flush issue. Verify that IOMMU settings are properly configured and test system stability after applying the update.

Recommended fix Moderate confidence

milanpi-sp3_1.0.0.7 or later

  1. Obtain the updated firmware version milanpi-sp3_1.0.0.7 or later from AMD's official support website for your specific Epyc processor model
  2. Follow AMD's standard firmware update procedure, which typically involves using the AMD firmware update tool or BMC/BIOS update utilities
  3. Ensure the system is powered on and stable during the firmware update process
  4. After updating, verify the firmware version has been successfully applied
Caveat Firmware updates carry inherent risks; ensure backups and a stable power supply before applying

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
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2021-26348 in production — separate from our analysis above.

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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