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AndroidOperating system · Google

CVE-2021-39752

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 Bubbles, there is a possible way to interfere with Bubbles due to a permissions bypass. 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-202756848

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 confidence

A permissions bypass vulnerability in Android's Bubbles feature (Android-12L) allows a local attacker to escalate privileges without additional execution privileges or user interaction. The vulnerability enables interference with the Bubbles notification system functionality.

MitigationApply the vendor-supplied Android system update/patch for Android-12L (A-202756848) to address the permissions bypass in the Bubbles 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
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 OS version
    Go to Settings > About Phone > Android version, or run 'getprop ro.build.version.release' via ADB shell, or use 'settings get global os_version'
    Affected if The installed version is exactly 12.1 (Android 12L)
  2. Verify Bubbles notification feature is active
    Check if Bubbles are enabled in Settings > Notifications > Bubbles, or inspect the Bubbles system service configuration via 'settings get system notification_bubbles'
    Affected if Bubbles notification feature is turned ON in system settings
  3. Inspect Bubbles system service permissions
    Review /data/system/users/0/package-restrictions.xml or check the BubblesManager service configuration via dumpsys notification --bubbles
    Affected if The Bubbles component lacks proper permission enforcement or shows unexpected permission grants
  4. Check for pending Bubbles notifications
    Run 'dumpsys notification --bubbles' to list active bubble notifications and their associated UIDs/processes
    Affected if There are active bubble notifications present in the system

A user is affected if their device runs Android 12.1 and has the Bubbles notification feature enabled, as the permissions bypass in the Bubbles component can then be exploited.

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 vendor-supplied Android system update/patch for Android-12L (A-202756848) to address the permissions bypass in the Bubbles component.

Recommended fix Moderate confidence

Android 12L with Security Patch Level >= February 2022 (or the specific patch level that addressed this vulnerability in the Android Security Bulletin)

  1. 1. Check the device's current Android Security Patch Level in Settings > About Phone > Security Patch Level
  2. 2. Verify if the device has received the Android Security Bulletin that addressed CVE-2021-39752 (typically released in early 2022)
  3. 3. If the device is running Android 12L and has not been updated to a security patch level that includes this fix, apply the latest available system update
  4. 4. On supported devices, ensure Android Auto and Bubbles features are updated through the Play Store or system updates
  5. 5. For enterprise or managed devices, ensure the mobile device management (MDM) solution is pushing the latest security patches
Caveat Security updates are cumulative; applying the latest patch should not introduce breaking changes but may include other feature modifications

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

Fix this in Android Scoped from the published advisory
  • Consultation4.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA3.0 h
25.0 hours of engineering $4,400
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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-2021-39752 in production — separate from our analysis above.

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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