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AndroidOperating system · Google

CVE-2023-21220

HIGH · 7.5 CVSS v3.1 Published 2023-06-28
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges 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
there is a possible use of unencrypted transport over cellular networks due to an insecure default value. This could lead to remote information disclosure with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-264590585References: N/A

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

This Android kernel vulnerability involves an insecure default value that causes unencrypted data transmission over cellular networks. Attackers on the same network path could intercept sensitive information being transmitted, leading to remote information disclosure. No user interaction or elevated privileges are required for exploitation.

MitigationApply the Android security patch for the kernel that changes the default transport behavior to use encryption over cellular networks. Until the patch is available, avoid transmitting sensitive data over cellular connections.

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:all versions

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

CVSS:3.1/AV:N/AC:L/PR:N/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 cellular data connectivity
    Check if the device has an active cellular data connection by reviewing network interfaces (e.g., using 'ip link show' or checking Android's network settings)
    Affected if Cellular data is enabled and active - any data transmitted over this connection may use the insecure default encryption setting
  2. Identify kernel version
    Run 'uname -r' or check /proc/version to obtain the kernel version, then compare against the Android security patch date for your device
    Affected if Kernel version predates the security patch that addresses CVE-2023-21220 - the insecure default value is still present
  3. Check for sensitive data transmission over cellular
    Review active network connections and apps using cellular data (e.g., via 'netstat' or Android's data usage settings)
    Affected if Sensitive data (credentials, personal information, financial details) is being transmitted while cellular is the active interface - this data could be intercepted due to unencrypted transmission by default
  4. Inspect kernel network configuration
    Examine kernel configuration files related to cellular/IPsec/encryption settings in /proc or sysctl values, if accessible
    Affected if The kernel is configured to allow unencrypted transmission as the default behavior over cellular interfaces

The device is affected if it uses cellular data and runs a kernel version predating the CVE-2023-21220 patch, as the insecure default causes potential unencrypted transmission of any data over cellular networks.

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 security patch for the kernel that changes the default transport behavior to use encryption over cellular networks. Until the patch is available, avoid transmitting sensitive data over cellular connections.

Recommended fix Moderate confidence

Latest Android release with May 2023 or later security patch level (A-264590585)

  1. Verify your current Android version and security patch level in Settings > About Phone > Android version
  2. Check for system updates in Settings > System > Software Update and install the latest available update
  3. If no update is available, contact your device manufacturer or carrier for the latest security patch
  4. As a temporary mitigation, avoid transmitting sensitive data over cellular networks until the patch is applied
  5. Ensure applications use HTTPS/TLS for all network communications
Caveat Major Android version upgrades may have compatibility issues with older applications or change device settings

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

Fix this in Android Scoped from the published advisory
  • Consultation4.0 h
  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,600
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Scan for this in your stack

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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-2023-21220 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