CVE-2021-3843
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 · uneditedA potential vulnerability in the SMI function to access EEPROM in some ThinkPad models may allow an attacker with local access and elevated privileges to execute arbitrary code.
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 confidenceA vulnerability in the System Management Interface (SMI) function that handles EEPROM access on certain ThinkPad models allows an authenticated attacker with local access and elevated privileges to execute arbitrary code via the SMI callback.
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<= 1.22<= 1.29<= 1.22<= 1.22<= 1.22<= 1.27<= 1.12<= 1.29<= 1.31CVSS 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
- High
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:H/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 your ThinkPad modelCheck the laptop model number on the chassis or via system information (Windows: msinfo32, Linux: dmidecode -s system-product-name)Affected if The model matches Thinkpad 11e 3rd Gen, Thinkpad 11e 4th Gen (I3/I5/I7/Celeron variants), Thinkpad 11e Yoga Gen 6, Thinkpad 13 Gen 2, or Lenovo L13
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Locate your current firmware versionAccess BIOS/UEFI setup on boot (F1 key) and check the BIOS version, or use Lenovo Vantage/System Update utility, or run 'dmidecode -s bios-version' on LinuxAffected if A firmware version is returned and can be compared to affected ranges
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Compare your firmware version against affected rangesMatch your model to its specific version thresholds: 11e 3rd Gen <= 1.22 or <=1.29, 11e 4th Gen I3/I5/I7 <=1.22, 11e 4th Gen Celeron <=1.27, 11e Yoga Gen 6 <=1.12, 13 Gen 2 <=1.29, L13 <=1.31Affected if Your installed firmware version is at or below the listed threshold for your specific model and variant
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Verify physical access and privilege requirementsConfirm the system is accessible to users with local access and administrative/root privilegesAffected if The attacker can physically access the device AND has elevated privileges to interact with the SMI interface
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Confirm EEPROM access functionalityThe vulnerability exists in the SMI callback handling EEPROM access; this is a firmware-level component, not a software serviceAffected if The system has not had the firmware updated to a version beyond the affected ranges listed
You are affected if your ThinkPad model is one of the listed models and your current BIOS/firmware version falls at or below the threshold specified for that model variant.
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 Lenovo firmware updates for affected ThinkPad models; restrict physical access to systems and enforce least-privilege principles for administrative accounts.
- Consultation2.0 h
- Implementation3.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-3843 — 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-2021-3843 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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