CVE-2021-39787
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 SystemUI, there is a possible arbitrary Activity launch due to a confused deputy. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is needed for exploitation.Product: AndroidVersions: Android-12LAndroid ID: A-202506934
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 confidenceIn SystemUI, an intent handling vulnerability allows a confused deputy attack where a malicious application can trigger the launch of arbitrary Activities with elevated privileges. The issue stems from insufficient validation of intents passed to Activity launching methods, enabling local privilege escalation without additional execution privileges, though user interaction is required.
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= 12.0CVSS 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
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/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 exactly 12.0Go to Settings > About Phone > Android version, or run 'adb shell getprop ro.build.version.release' via command lineAffected if The version shows 12.0 exactly (not 12L, 13, or later)
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Check security patch levelGo to Settings > About Phone > Security patch level, or run 'adb shell getprop ro.build.version.security_patch'Affected if The patch level is earlier than the Android-12L security update (the fix release)
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Confirm SystemUI package versionRun 'adb shell dumpsys package com.android.systemui' and look for the versionName or versionCode in the outputAffected if The SystemUI version is from the unpatched Android 12.0 release and no OTA/system update has been applied
A device is affected if it is running Android 12.0 (exactly) with a security patch level predating the Android-12L update, as the vulnerability exists in the original SystemUI intent handling code for that specific version.
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 (or later) containing the fix for this SystemUI vulnerability. For custom AOSP builds, implement proper intent validation and permission checks before launching Activities in SystemUI components.
Android 12L (API level 32) with latest security patch or upgrade to Android 13
- 1. Navigate to Settings > System > System Update on the affected Android device
- 2. Check for and install any available system updates
- 3. Ensure the device receives the latest Android security patch level that addresses CVE-2021-39787
- 4. After updating, verify the System UI version reflects the patched release
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation6.0 h
- Implementation12.0 h
- Testing10.0 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 $9,504.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-39787 — 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-2021-39787 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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