dbcve.org
Thinkbook 14 Iml FirmwareOperating system · Lenovo

CVE-2022-1891

HIGH · 7.8 CVSS v3.1 Published 2023-01-26
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
80/100
Remediation priority · High
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
A buffer overflow in the SystemLoadDefaultDxe driver in some Lenovo Notebook products may allow an attacker with local 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 · high confidence

A buffer overflow vulnerability exists in the SystemLoadDefaultDxe UEFI driver on certain Lenovo notebook devices. An attacker with local access and privileges can exploit this buffer overflow to execute arbitrary code outside the operating system, at the firmware/UEFI level.

MitigationApply the Lenovo firmware/BIOS update for affected notebooks. Restrict physical access to systems and ensure least-privilege principles for local users.

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
Thinkbook 14 Iml FirmwareOperating system
Affected:< cjcn38ww
Thinkbook 14 Iil FirmwareOperating system
Affected:< djcn28ww
Thinkbook 15 Iil FirmwareOperating system
Affected:< djcn28ww
Thinkbook 15 Iml FirmwareOperating system
Affected:< cjcn38ww
Yoga C640 13iml Lte FirmwareOperating system
Affected:< chcn28ww
Yoga C640 13iml FirmwareOperating system
Affected:< chcn28ww

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
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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify the exact Lenovo notebook model
    Check the device label on the bottom of the notebook or look up system information in Windows (Settings > System > About) or Linux (cat /sys/class/dmi/id/product_name)
    Affected if The model does not match one of the affected products: Thinkbook 14 Iml, Thinkbook 14 Iil, Thinkbook 15 Iil, Thinkbook 15 Iml, Yoga C640 13iml Lte, or Yoga C640 13iml
  2. Determine the current UEFI/BIOS firmware version
    On Windows, open Lenovo Vantage or Lenovo System Update and check the BIOS version, or run 'wmic bios get smbiosbiosversion' in Command Prompt. On Linux, run 'dmidecode -s bios-version' or check /sys/class/dmi/id/bios_version
    Affected if Unable to retrieve the firmware version from the system
  3. Compare your firmware version against affected ranges
    Match your model to its corresponding vulnerable version threshold: Thinkbook 14 Iml and Thinkbook 15 Iml are affected below cjcn38ww; Thinkbook 14 Iil and Thinkbook 15 Iil are affected below djcn28ww; Yoga C640 13iml Lte and Yoga C640 13iml are affected below chcn28ww
    Affected if The installed firmware version is lower (older) than the version threshold for your specific model, or the version cannot be determined to be above the threshold
  4. Confirm the SystemLoadDefaultDxe UEFI driver is present
    This is a UEFI driver that loads during the boot process. It is typically not directly visible to end users, but its presence can be inferred if the firmware version is confirmed vulnerable. No user-accessible command can directly enumerate this driver
    Affected if This check is informational only; the driver presence is assumed on affected models with vulnerable firmware versions

You are affected if your Lenovo notebook model matches one of the six listed products AND your current firmware version is below the specified version threshold for that model.

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 the Lenovo firmware/BIOS update for affected notebooks. Restrict physical access to systems and ensure least-privilege principles for local users.

Recommended fix High confidence

Firmware version cjcn38ww (ThinkBook 14/15 IML), djcn28ww (ThinkBook 14/15 IIL), or chcn28ww (Yoga C640 13IML LTE/13IML) - or later

  1. Visit support.lenovo.com and locate the drivers & software section for your specific Lenovo product model
  2. Identify your product number (e.g., ThinkBook 14 IML, Yoga C640 13IML)
  3. Navigate to the BIOS/UEFI firmware section
  4. Download the firmware version cjcn38ww (for IML models), djcn28ww (for IIL models), or chcn28ww (for Yoga C640 models) - or newer
  5. Review the firmware update instructions on Lenovo's support page
  6. Run the firmware update utility or use Lenovo Vantage/System Update to apply the new firmware
  7. Allow the system to restart and complete the firmware update process - do not interrupt power during this process
Caveat Firmware updates carry inherent risk if interrupted; ensure stable power and do not interrupt the update process

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

Fix this in Thinkbook 14 Iml Firmware Scoped from the published advisory
  • Consultation6.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,880
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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-2022-1891 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