CVE-2021-39676
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 writeThrowable of AndroidFuture.java, there is a possible parcel serialization/deserialization mismatch due to improper input validation. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-11Android ID: A-197228210
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 confidenceA parcel serialization/deserialization mismatch in AndroidFuture.java's writeThrowable method allows local privilege escalation due to improper input validation. The vulnerability stems from incorrect validation during parcel data handling, enabling a malicious application to elevate privileges without user interaction on Android-11 devices.
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= 11.0CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Verify Android version is 11.0Go to Settings > About Phone > Android version, or run 'getprop ro.build.version.release' via ADB shellAffected if Android version is exactly 11.0 (API level 30)
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Check Security Patch LevelGo to Settings > About Phone > Security patch level, or run 'getprop ro.build.version.security_patch' via ADB shellAffected if Security patch level is earlier than 2021-11-05 (vulnerability is unpatched)
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Confirm AndroidFuture framework component existsCheck for the presence of the Android framework's AndroidFuture class in the system - this can be done by examining system logs or using a device forensics tool to verify the parcel handling code is present on the deviceAffected if The Android framework parcel handling code (AndroidFuture.java-based components) exists and processes parcel data without the November 2021 validation fix
The device is affected if it runs Android 11.0 and has a Security Patch Level earlier than November 2021, meaning the parcel deserialization validation fix has not been applied.
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 · scopedApply the Android security patch for CVE-2021-39676 (Android-11) which corrects the parcel deserialization validation in AndroidFuture.java. Organizations should ensure affected devices receive the November 2021 or later security update.
Android 12 or later, or Android 11 with December 2021 security patch level
- Navigate to Settings on the Android device
- Go to System > System Update (or Settings > About Phone > Software Update)
- Check for and install any available system updates
- Verify the security patch level is December 2021 (2021-12-01) or later under Settings > About Phone > Security Patch Level
- If no update is available, contact the device manufacturer for the security patch
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA3.0 h
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 locallyCheck whether your project pulls in CVE-2021-39676 — 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-2021-39676 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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