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AndroidOperating system · Google

CVE-2021-39757

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 PermissionController, there is a possible permission bypass due to an unsafe PendingIntent. This could lead to local information disclosure with User execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-12LAndroid ID: A-176094662

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 PermissionController, an unsafe PendingIntent allows a permission bypass that enables local information disclosure. The vulnerability stems from the PendingIntent not being properly secured, potentially allowing an attacker to hijack the intent and access sensitive permission-related data without triggering standard permission checks.

MitigationApply the Android-12L security patch; for custom implementations, ensure PendingIntents use FLAG_IMMUTABLE or FLAG_UPDATE_CURRENT with proper intent specificity to prevent hijacking.

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
    Check the device Settings > About Phone > Android version. The affected version is specifically Android 12.1.
    Affected if The device is running Android version 12.1 exactly.
  2. Check security patch level
    Go to Settings > About Phone > Security patch level. Compare the installed patch level against the Android-12L security patch that addresses this issue.
    Affected if The security patch level is earlier than the Android-12L fix.
  3. Identify PermissionController component
    On the Android device, locate the PermissionController system app in Settings > Apps > Show system apps. Check the app version information.
    Affected if The PermissionController app version corresponds to the Android 12.1 build.

A device is affected if it is running exactly Android 12.1 and has not received the Android-12L security patch that fixes the unsafe PendingIntent in PermissionController.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the Android-12L security patch; for custom implementations, ensure PendingIntents use FLAG_IMMUTABLE or FLAG_UPDATE_CURRENT with proper intent specificity to prevent hijacking.

Fix this in Android Scoped from the published advisory
  • Consultation2.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,800
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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-2021-39757 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