dbcve.org
AndroidOperating system · Google

CVE-2021-39788

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 TelecomManager, there is a possible way to check if a particular self managed phone account was registered on the device due to side channel information disclosure. 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-191768014

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 TelecomManager on Android 12L, a side-channel vulnerability allows a local attacker to determine whether a specific self-managed phone account was registered on the device. The information disclosure occurs without requiring additional execution privileges or user interaction.

MitigationThis is a framework-level vulnerability requiring a security patch from the Android ecosystem. Organizations should ensure end-user devices receive the latest Android security updates from device manufacturers.

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. Check Android version is 12.1
    Go to Settings > About Phone > Android version or run 'getprop ro.build.version.release' via ADB
    Affected if Version is exactly 12.1 (Android 12L)
  2. Verify TelecomManager is present
    Check for TelecomManager API availability on the device by examining /system/framework/services.jar or checking telecom manager service via 'dumpsys telecom' command
    Affected if TelecomManager service is accessible on the device
  3. Determine if self-managed phone accounts exist
    Run 'adb shell dumpsys telecom' and look for entries indicating self-managed connection services or phone accounts registered via TelecomManager
    Affected if Any self-managed phone accounts are registered on the device
  4. Check if apps can access TelecomManager
    Review installed applications for those with TelecomManager permissions or that interact with phone account registration APIs
    Affected if Applications with telecom-related permissions are present and can potentially query account information

Device is affected if running Android 12.1 (12L) and has TelecomManager accessible with self-managed phone accounts registered, allowing any local app to enumerate those accounts.

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

This is a framework-level vulnerability requiring a security patch from the Android ecosystem. Organizations should ensure end-user devices receive the latest Android security updates from device manufacturers.

Recommended fix High confidence

Android 12L with February 2022 security patch or later

  1. Check your device's current Android security patch level in Settings > About Phone > Android version
  2. Verify if your device has received the February 2022 Android Security Patch Level or later
  3. If not patched, check for system updates: Settings > System > Software Update
  4. Apply any available system updates that include the February 2022 security patch or newer
  5. After updating, confirm the security patch level shows February 2022 or later
Caveat Security updates for Android 12L typically have minimal breaking changes; updates are cumulative and focus on bug fixes and security patches

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

Fix this in Android Scoped from the published advisory
  • Consultation2.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,100
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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-2021-39788 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