CVE-2021-39782
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 · uneditedIn Telephony, there is a possible unauthorized modification of the PLMN SIM file due to a missing permission check. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android-12LAndroid ID: A-202760015
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 confidenceIn Android-12L Telephony, a missing permission check allows unauthorized modification of the PLMN (Public Land Mobile Network) SIM file. This local privilege escalation requires no additional execution privileges or user interaction to exploit.
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= 12.0CVSS 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
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/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 checksWork through these to decide whether this CVE applies to you.
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Check Android versionGo to Settings > About Phone > Android version or run 'getprop ro.build.version.release' via ADB shellAffected if Version is exactly 12.0 (Android-12L)
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Verify Telephony module is presentCheck if /system/framework/telephony-common.jar exists, or run 'dumpsys telephony' to confirm the Telephony service is activeAffected if Telephony module is installed and running on Android 12.0
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Confirm PLMN SIM access capabilityCheck if the device has a SIM card slot and supports PLMN operations; verify telephony permissions status via 'dumpsys package <telephony package>'Affected if Device supports SIM-based telephony on Android 12.0, exposing the missing permission check
You are affected if your device runs Android 12.0 with the Telephony module active and PLMN SIM file operations are accessible without proper permission validation.
Generated from the published advisory. Verify against your own configuration.
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 · scopedApply the Android-12L system update containing the security patch for A-202760015 which implements proper permission validation before PLMN SIM file modification operations.
Android-13 or later, or apply the January 2022 (or subsequent) Android security patch that addresses CVE-2021-39782
- Check your Android device for available system updates in Settings > System > Software Update
- Apply the latest Android security patch update (typically the January 2022 security patch or later, which addresses this vulnerability in Telephony)
- Verify the update was successfully installed by checking Settings > About Phone > Android security patch level
- Ensure the device is running a build that includes the fix for Android ID A-202760015
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-39782 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-39782 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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