CVE-2021-24027
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 · uneditedA cache configuration issue prior to WhatsApp for Android v2.21.4.18 and WhatsApp Business for Android v2.21.4.18 may have allowed a third party with access to the device’s external storage to read cached TLS material.
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 confidenceA cache configuration vulnerability in WhatsApp for Android and WhatsApp Business for Android versions prior to 2.21.4.18 stored TLS cryptographic material (session keys, certificates) in a location accessible via external storage. Any application with storage permissions or anyone with physical access to the device's external storage could read cached TLS material, enabling man-in-the-middle attacks or session 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< 2.21.4.18< 2.21.4.18CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Check WhatsApp versionOpen WhatsApp, tap the three-dot menu > Settings > Help > About. Look for the version number under 'Version'.Affected if The version number is less than 2.21.4.18 (for example, 2.21.4.17 or earlier)
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Check WhatsApp Business versionOpen WhatsApp Business, tap the three-dot menu > Settings > Help > About. Look for the version number under 'Version'.Affected if The version number is less than 2.21.4.18 (for example, 2.21.4.17 or earlier)
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Review apps with storage permissionsGo to Android Settings > Apps > (tap each app) > Permissions. Look for 'Storage' or 'Files and media' permissions granted to third-party apps you do not trust.Affected if Any untrusted or unknown application has been granted storage permissions on the device
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Check for sideloaded or untrusted appsReview the list of installed apps in Settings > Apps. Look for any applications installed from unknown sources or apps you did not intentionally install, especially those requesting storage access.Affected if Sideloaded or untrusted applications with storage access are present on the device
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Verify device physical securityConsider whether the device has been left unattended, shared with others, or could have been accessed by unauthorized persons who might have read external storage content.Affected if The device has been physically accessible to untrusted individuals who could have extracted the exposed TLS material
You are affected if WhatsApp or WhatsApp Business for Android is installed at a version earlier than 2.21.4.18 AND either untrusted apps have storage permissions or the device has been physically accessible to unauthorized users.
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 data2.21.4.18
Update WhatsApp and WhatsApp Business for Android to version 2.21.4.18 or later, which stores TLS material in secure internal storage. Users should also review app permissions and avoid installing untrusted applications that request storage access.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-24027 — 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-2021-24027 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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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.
- 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