dbcve.org
AndroidOperating system · Google

CVE-2021-39750

HIGH · 7.8 CVSS v3.1 Published 2022-03-30
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
80/100
Remediation priority · High
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 PackageManager, there is a possible way to change the splash screen theme of other apps due to a missing permission check. 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-206474016

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 missing permission check in Android's PackageManager allows any installed app to modify the splash screen theme of other applications without authorization. This local privilege escalation vulnerability affects Android-12L and enables a malicious app to alter how other apps display their launch splash screens.

MitigationApply the Android security patch for Android-12L (or later versions) from Google. No user interaction is required for exploitation, so immediate patching is critical.

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:= 12.1

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
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 checks

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

  1. Check Android version via ADB
    Run 'adb shell getprop ro.build.version.release' to retrieve the Android OS version
    Affected if The output shows version 12.1 (Android 12L)
  2. Check Android SDK version via ADB
    Run 'adb shell getprop ro.build.version.sdk' to retrieve the SDK level
    Affected if The output shows SDK level 32 (Android 12L)
  3. Verify PackageManager service accessibility
    Check if PackageManager service is accessible by running 'adb shell dumpsys package' and confirming the service responds
    Affected if PackageManager service is running and responds (confirms the vulnerable component exists)
  4. Check for installed apps with signature permissions
    Use 'adb shell pm list packages -s' to list system apps, then inspect if any app has MODIFY_SPLASH_SCREEN or similar splash theme permissions
    Affected if Any installed app can modify splash screen themes due to missing permission enforcement in PackageManager

A device is affected if it is running Android version 12.1 (Android-12L) with the vulnerable PackageManager that lacks the permission check for splash screen theme modification.

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 the Android security patch for Android-12L (or later versions) from Google. No user interaction is required for exploitation, so immediate patching is critical.

Recommended fix High confidence

Apply the January 2022 Android Security Update (or subsequent monthly patches) which contains the fix for CVE-2021-39750 in PackageManager

  1. Ensure the Android device is running the latest available Android security update. Go to Settings > Security > Google Security Patch Level and verify the date is January 2022 or later.
  2. If an update is available, download and install it via Settings > System > System Update > Check for Update.
  3. After updating, verify the fix by confirming the Google Security Patch Level shows the January 2022 patch or later under Settings > Security.
Caveat Standard Android monthly security updates typically have no breaking changes; they are cumulative patches that include bug fixes and security improvements without altering functionality

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

Fix this in Android Scoped from the published advisory
  • Consultation3.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA5.0 h
28.0 hours of engineering $4,740
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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-2021-39750 in production — separate from our analysis above.

No notes yet

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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