dbcve.org
AndroidOperating system · Google

CVE-2021-39751

MEDIUM · 5.5 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 →
57/100
Remediation priority · Elevated
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 Settings, there is a possible way to read Bluetooth device names without proper permissions due to a missing permission check. This could lead to local information disclosure with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-12LAndroid ID: A-172838801

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

In Android Settings app (Android-12L), a missing permission check allows local apps or processes to read Bluetooth device names without proper Bluetooth permissions. This constitutes local information disclosure as nearby Bluetooth device names (which often contain personal identifiers like user names) can be accessed without authorization.

MitigationApply the Android-12L patch which adds the missing permission check in the Settings app to enforce proper Bluetooth permission validation before allowing device name access.

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
None
Availability
None

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

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. Verify Android version is 12.1
    Go to Settings > About Phone > Android version or run 'getprop ro.build.version.release' in ADB shell
    Affected if Android version is 12.1 (Android-12L) - other versions are not affected by this specific CVE
  2. Confirm the device is not patched
    Check if the Google monthly security patch level (Settings > About Phone > Security patch level) is after February 2022, or compare Settings app version to the patched build
    Affected if Security patch level is February 2022 or earlier, indicating the missing permission check fix is not applied
  3. Identify installed apps with Bluetooth access
    Review installed applications in Settings > Apps > Permissions > Bluetooth, or run 'dumpsys package' to list apps with BLUETOOTH_CONNECT or BLUETOOTH permission
    Affected if Any application with BLUETOOTH_CONNECT permission exists on the device - such an app could exploit the missing permission check in Settings to read Bluetooth device names
  4. Check Settings app permissions state
    Use ADB command: 'dumpsys package com.android.settings | grep -i bluetooth' to inspect the Settings app's permission grants for Bluetooth-related access
    Affected if Settings app lacks explicit permission enforcement for reading Bluetooth device names (this is the vulnerable state before the patch)

A device is affected if it runs Android 12.1 (Android-12L) with a security patch level of February 2022 or earlier, allowing any local app with Bluetooth permissions to read nearby Bluetooth device names without additional authorization.

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-12L patch which adds the missing permission check in the Settings app to enforce proper Bluetooth permission validation before allowing device name access.

Recommended fix Moderate confidence

Update to the latest available Android security patch level for Android-12L (or migrate to a newer Android version if available)

  1. Navigate to Settings on the Android device
  2. Tap on System or About Phone
  3. Tap on System Update or Software Update
  4. Check for and install any available updates
  5. Ensure the device receives the latest Android security patch (published after the vulnerability disclosure date)

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

Fix this in Android Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing3.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,750
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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-2021-39751 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