dbcve.org
AndroidOperating system · Google

CVE-2021-0396

CRITICAL · 9.8 CVSS v3.1 Published 2021-03-10
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges 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
In Builtins::Generate_ArgumentsAdaptorTrampoline of builtins-arm.cc and related files, there is a possible out of bounds write due to an incorrect bounds check. This could lead to remote code execution in an unprivileged process with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-8.1 Android-9 Android-10 Android-11Android ID: A-160610106

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 bounds check error in Builtins::Generate_ArgumentsAdaptorTrampoline in the V8 JavaScript engine (ARM implementation) allows an out-of-bounds memory write, enabling remote code execution in an unprivileged browser process without user interaction.

MitigationApply Android security updates for Android 8.1 through 11 that include the V8 engine patch; this vulnerability is fixed in Android's monthly security patches.

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
AndroidOperating system
Affected:= 8.1= 9.0= 10.0= 11.0

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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/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 checks

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

  1. Check Android OS version
    Go to Settings > About Phone > Android version, or run 'getprop ro.build.version.release' via ADB shell
    Affected if The reported version is 8.1, 9.0, 10.0, or 11.0
  2. Identify the V8-containing component
    Check if Chrome, Chrome-based browser, or WebView is in use - run 'pm list packages | grep -E "(chrome|webview)"' via ADB shell
    Affected if Any Chrome or WebView package is installed (V8 is embedded in these by default)
  3. Check security patch level
    Go to Settings > About Phone > Security patch level, or run 'getprop ro.build.version.security_patch' via ADB shell
    Affected if The patch level is earlier than the June 2021 Android security update (dates before 2021-06-01)
  4. Verify WebView provider
    For Android 10 and below: go to Settings > Apps > Android System WebView > Version. For Android 11+: check Settings > Apps > See all apps > Android System WebView
    Affected if WebView version is unpatched and Android version is 8.1-11.0

A device is affected if it runs Android 8.1, 9.0, 10.0, or 11.0 with a security patch level before June 2021 and has Chrome or WebView containing the vulnerable V8 engine enabled.

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 Android security updates for Android 8.1 through 11 that include the V8 engine patch; this vulnerability is fixed in Android's monthly security patches.

Recommended fix High confidence

Android 11 with March 2021 security patch level (or later monthly patch)

  1. 1. Check current Android version by going to Settings > About Phone > Android version
  2. 2. Check the installed security patch level by going to Settings > About Phone > Security patch level
  3. 3. If the security patch level is earlier than March 2021, initiate a system update: Settings > System > System Update > Check for updates
  4. 4. Install any available security updates to receive the fix for CVE-2021-0396
  5. 5. Verify the security patch level shows March 2021 or later after the update completes
Caveat Minimal risk - security updates are backward compatible; ensure sufficient battery before updating

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

Fix this in Android Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,560
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,096.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2021-0396 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2021-0396 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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