CVE-2021-39719
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 · uneditedIn lwis_top_register_io of lwis_device_top.c, there is a possible out of bounds write due to an integer overflow. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-205995178References: N/A
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 confidenceInteger overflow in lwis_top_register_io function in lwis_device_top.c causes out-of-bounds write, allowing local privilege escalation from System privileges to root on Android kernel.
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 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
- 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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Confirm Android device is in useCheck if the system is running Android (uname -a shows 'Android' or check /system/build.prop for ro.build.fingerprint)Affected if System is not Android - this CVE does not apply
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Check Android security patch levelReview Settings > About Phone > Security Patch Level or run 'getprop ro.build.version.security_patch'Affected if Security patch level is earlier than the vendor release date for this fix - may indicate unpatched state
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Identify kernel versionRun 'uname -r' or check /proc/version to obtain kernel release stringAffected if Kernel version predates the fix release for this CVE
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Verify lwis driver presenceCheck if lwis.ko or lwis_device_top.c driver is loaded in kernel - run 'lsmod | grep lwis' or check /sys/module/ for lwis directoryAffected if lwis driver is not present in the kernel - the attack surface does not exist
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Confirm System privilege contextIdentify if any service or process with System-level privileges is in use - check running services via 'dumpsys' or process list with 'ps -A' for processes running with System UID (1000)Affected if No System-privileged processes or services are running - the privilege escalation path may not be reachable
The environment is likely affected if it runs Android with a kernel version or security patch level predating the CVE fix, and the lwis driver is present in the kernel with System-privileged processes in use.
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 dataPatch the kernel with the vendor-provided security update that addresses the integer overflow in the lwis device driver. Given System privilege requirement, this likely affects privileged system services or drivers.
- Consultation4.0 h
- Implementation8.0 h
- Testing12.0 h
- Review / QA6.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $8,192.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-39719 — 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-2021-39719 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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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.
- 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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