CVE-2021-26317
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 · uneditedFailure to verify the protocol in SMM may allow an attacker to control the protocol and modify SPI flash resulting in a potential arbitrary code execution.
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 · high confidenceThis is a firmware vulnerability in System Management Mode (SMM) where the protocol is not properly verified, allowing an attacker to control the protocol and modify SPI flash contents. Since SMM operates at the highest privilege level on x86 processors, successful exploitation could lead to arbitrary code execution with firmware-level persistence.
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 dataall versionsall versionsall versionsall versionsall versionsall versionsall versionsall versionsCVSS 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
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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 checksWork through these to decide whether this CVE applies to you.
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Identify the AMD processor modelRun 'wmic cpu get name' or check system information to confirm the processor is one of: Ryzen 3 2200u, Ryzen 5300g, Ryzen 5300ge, Ryzen 5600g, Ryzen 5600ge, Ryzen 5600x, or Ryzen 5700g. For Radeon Software, check installed AMD software version via Programs and Features.Affected if The system uses any of the listed AMD processors or Radeon Software products, since all versions of these are affected.
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Check the current BIOS/firmware versionRun 'wmic bios get smbiosbiosversion' or enter BIOS/UEFI setup during boot to view the BIOS version. Compare against the version delivered with the vendor patch for this CVE.Affected if The installed BIOS version predates the vendor-provided patch for CVE-2021-26317, or the system firmware has not been updated since the patch release date.
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Verify SMM status and configurationUse tools such as 'dmidecode -t system' (Linux) or check UEFI/BIOS settings for SMM features. On Windows, use 'msinfo32' or specialized firmware analysis tools like chipsec to query SMM configuration.Affected if SMM is enabled and the firmware remains unpatched, which is the default state for affected systems.
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Inspect SPI flash integrityUse hardware-level tools or platform-specific firmware utilities (such as AMD's flash programming tools or chipsec) to read the SPI flash contents and verify integrity against a known-good baseline or hash.Affected if The SPI flash contents show unauthorized modifications or the integrity check fails, indicating potential exploitation.
A system is affected if it contains any of the listed AMD processors or Radeon Software products, runs unpatched firmware/BIOS, and has SMM enabled.
Generated from the published advisory. Verify against your own configuration.
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.
From vendor dataApply the vendor-provided firmware/BIOS update that addresses the SMM protocol verification failure. Verify SPI flash integrity after the update and consider disabling SMM if not required by the system.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-26317 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-26317 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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