CVE-2021-39759
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 libstagefright, there is a possible out of bounds write due to an integer overflow. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-12LAndroid ID: A-180200830
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 vulnerability in libstagefright's media processing allows an integer overflow to cause an out-of-bounds write, enabling local privilege escalation without user interaction or additional privileges. The flaw exists in Android-12L's media framework component.
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= 12.1CVSS 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 12.1 (Android-12L)Check the Android build number via Settings > About Phone > Build Number, or run 'getprop ro.build.version.release' in ADB shellAffected if The device is running Android version 12.1 or Android-12L specifically (version equals 12.1)
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Confirm libstagefright library is presentCheck for the existence of libstagefright.so in /system/lib/ or /system/lib64/ using 'ls -la /system/lib*/libstagefright.so' via ADBAffected if The libstagefright library exists on the device (it is present by default in Android-12L)
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Verify media framework is enabledConfirm Stagefright media server is running via 'ps -A | grep stagefright' in ADB shell, or check that media apps can access the media frameworkAffected if The Stagefright media service is active (this is default behavior in Android-12L)
The device is affected if it runs Android version 12.1 (Android-12L) and contains the libstagefright library, as the integer overflow vulnerability exists in this specific version's media framework component.
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-12L security patch (A-180200830) to address the integer overflow in libstagefright; ensure devices receive timely Google security updates.
Android-12L with January 2022 Security Patch Level or later
- Check current Android security patch level: Go to Settings > About Phone > Security Patch Level
- Ensure the device receives and installs the January 2022 Android Security Update or later
- If the device is no longer receiving monthly security updates, consider upgrading to a device that still receives security patches
- For enterprise/managed devices, ensure the mobile device management (MDM) policy pushes the latest security updates
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing12.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,616.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-39759 — 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-2021-39759 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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