dbcve.org
AndroidOperating system · Google

CVE-2021-0933

HIGH · 8.0 CVSS v3.1 Published 2021-12-15
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
83/100
Remediation priority · High
No privileges

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 onCreate of CompanionDeviceActivity.java or DeviceChooserActivity.java, there is a possible way for HTML tags to interfere with a consent dialog due to improper input validation. This could lead to remote escalation of privilege, confusing the user into accepting pairing of a malicious Bluetooth device, with no additional execution privileges needed. User interaction is needed for exploitation.Product: AndroidVersions: Android-10 Android-11 Android-12 Android-9Android ID: A-172251622

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's Bluetooth companion device pairing functionality (CompanionDeviceActivity.java or DeviceChooserActivity.java), improper input validation allows HTML tags to be injected into the device consent dialog. This HTML injection can manipulate the dialog's appearance and text, deceiving users into approving pairing with a malicious Bluetooth device.

MitigationThe vulnerability requires an AOSP framework code fix to properly sanitize/validate input in the affected Activity classes before rendering in the dialog. Users should avoid pairing with untrusted Bluetooth devices and apply available Android security updates.

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:= 9.0= 10.0= 11.0= 12.0

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
Adjacent
Complexity
Low
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:A/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 checks

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

  1. Check Android version
    Go to Settings > About Phone > Android version, or run 'getprop ro.build.version.release' via ADB
    Affected if The version is 9.0, 10.0, 11.0, or 12.0
  2. Confirm Bluetooth is enabled
    Check Settings > Bluetooth toggle, or run 'settings get global bluetooth_on' via ADB
    Affected if Bluetooth is turned on (value returns 1)
  3. Identify if Companion Device Manager is in use
    Check for apps using companion device pairing - look for 'CompanionDeviceManager' in installed apps via 'pm list packages' or inspect app permissions for ACCESS_FINE_LOCATION with BLUETOOTH_CONNECT
    Affected if Any app on the device has requested companion device pairing permissions and the Bluetooth consent dialog is shown

You are affected if your Android device runs version 9.0, 10.0, 11.0, or 12.0 and you use Bluetooth companion device pairing with untrusted devices, as the HTML injection vulnerability exists in the framework's DeviceChooserActivity or CompanionDeviceActivity classes.

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

The vulnerability requires an AOSP framework code fix to properly sanitize/validate input in the affected Activity classes before rendering in the dialog. Users should avoid pairing with untrusted Bluetooth devices and apply available Android security updates.

Recommended fix Moderate confidence

Android 12L (API level 32) or later, or apply the Android January 2022 Security Patch Level (SPL) or later

  1. 1. Navigate to Settings > System > Security & privacy (or Settings > Security on some devices)
  2. 2. Tap on 'Security update' or 'Google Security Policy' to check current patch level
  3. 3. Go to Settings > System > System update (or Settings > About phone > Software update)
  4. 4. Check for and install any available system updates
  5. 5. After updating, verify the patch level includes the fix for Android ID A-172251622
Caveat Major Android version upgrades may introduce UI changes or remove compatibility with older apps; backup data before upgrading

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

Fix this in Android Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,760
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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-2021-0933 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