CVE-2021-42849
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 weak default password for the serial port was reported in some Lenovo Personal Cloud Storage devices that could allow unauthorized device access to an attacker with physical access.
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 confidenceLenovo Personal Cloud Storage devices contain a weak default password for the serial port interface. An attacker with physical access to the device can connect to the serial console and gain unauthorized administrative access using this default credentials.
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< 5.3.6.a1< 5.3.6.t1< 5.3.8.x1< 5.3.8.t2< 5.3.7.t2-proCVSS 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
- Physical
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:P/AC:L/PR:N/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 Lenovo Personal Cloud Storage modelLocate the model number label on the device or access the device admin interface to confirm the exact model (A1, T1, X1, T2, or T2pro)Affected if The device is one of these five models and you need to determine which version range applies
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Check the installed firmware versionAccess the device admin interface via web browser or check via the companion mobile/desktop application. Navigate to Settings or System Information to view the current firmware versionAffected if The firmware version falls below the threshold for your model: A1 < 5.3.6.a1, T1 < 5.3.6.t1, X1 < 5.3.8.x1, T2 < 5.3.8.t2, T2pro < 5.3.7.t2-pro
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Verify if serial console is accessible on your deviceInspect the device casing for exposed serial port pins (typically 3-4 pins near the edge). Check device documentation or settings for serial console status. On the device itself or in admin settings, look for serial/console access optionsAffected if Serial console pins are exposed and accessible, or serial console is enabled in the device settings
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Confirm whether the default serial password has been changedIf you have access to the serial console, attempt to log in. If you do not have prior knowledge of the password, check any documentation, configuration backups, or admin scripts for custom password configurationsAffected if The serial console still uses the factory default password, or you cannot locate evidence that a unique password was configured
Your device is affected if it is a Lenovo A1, T1, X1, T2, or T2pro running firmware below the specified version AND the serial console remains accessible with the default password unchanged.
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.
dbcve · scoped5.3.6.t15.3.6.a15.3.7.t2-pro
Change the default serial port password to a strong, unique value and restrict physical access to the device. If serial console access is not required, disable it or implement additional authentication controls.
A1: 5.3.6.a1 or higher | T1: 5.3.6.t1 or higher | X1: 5.3.8.x1 or higher | T2: 5.3.8.t2 or higher | T2pro: 5.3.7.t2-pro or higher
- 1. Identify your Lenovo Personal Cloud Storage device model (A1, T1, X1, T2, or T2pro)
- 2. Check the current firmware version installed on your device through the device management interface
- 3. Navigate to the official Lenovo support page (iknow.lenovo.com.cn) or device management panel to download the latest firmware update
- 4. Apply the firmware update following the manufacturer's instructions
- 5. Verify the firmware has been updated to the minimum fixed version for your model
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation1.0 h
- Implementation1.0 h
- Testing1.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,200.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-42849 — 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-2021-42849 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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