CVE-2019-2021
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 rw_t3t_act_handle_ndef_detect_rsp of rw_t3t.cc, there is a possible out-of-bound read due to a missing bounds check. This could lead to local information disclosure with no additional execution privileges needed. User interaction is needed for exploitation.Product: AndroidVersions: Android-7.0 Android-7.1.1 Android-7.1.2 Android-8.0 Android-8.1 Android-9Android ID: A-120428041
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 confidenceAn out-of-bounds read vulnerability exists in the NFC T3T (Type 3 Tag) protocol handler function rw_t3t_act_handle_ndef_detect_rsp in rw_t3t.cc. The function fails to validate buffer bounds before reading data from an NDEF (NFC Data Exchange Format) detection response, potentially allowing a local attacker to read beyond allocated memory boundaries and access sensitive information.
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= 7.0= 7.1.1= 7.1.2= 8.0= 8.1= 9.0CVSS 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
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/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 checksWork through these to decide whether this CVE applies to you.
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Identify the Android versionCheck the device settings under Settings > About Phone > Android version, or run 'getprop ro.build.version.release' in a terminal or ADB shellAffected if The version is 7.0, 7.1.1, 7.1.2, 8.0, 8.1, or 9.0 (exact match to affected list)
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Confirm NFC hardware capability existsVerify the device has NFC hardware by checking Settings > Connections > NFC (or Settings > Network & Internet > NFC), or by checking for the 'nfc' service via 'getprop' commandAffected if The device lacks NFC hardware, the vulnerability cannot be triggered
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Determine if NFC is enabledCheck the NFC toggle in Settings > Connections > NFC or Settings > Network & Internet > NFC. NFC must be turned on for the T3T handler code to be exercisedAffected if NFC is disabled, the vulnerable code path is not active
The device is affected if it runs Android 7.0, 7.1.1, 7.1.2, 8.0, 8.1, or 9.0 AND has NFC hardware that is enabled, since the out-of-bounds read occurs in the T3T protocol handler when processing NDEF detection responses.
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.
From vendor dataApply the Android security patch (Android-7.0 through Android-9) that includes the bounds check fix for the NFC T3T handler. Users should exercise caution with NFC interactions until the device receives the vendor update.
- Consultation2.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,808.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-2021 — 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-2019-2021 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
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