CVE-2021-40038
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 · uneditedThere is a Double free vulnerability in the AOD module in smartphones. Successful exploitation of this vulnerability may affect service integrity.
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 confidenceA double free vulnerability exists in the Always-On Display (AOD) module of certain smartphone firmware. This memory corruption flaw allows an attacker to potentially execute arbitrary code or cause denial of service by freeing the same memory pointer twice, leading to heap corruption and compromised service integrity.
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< 2.0= 11.0.0= 12.0.0= 4.0.0CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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 operating systemCheck the device settings to determine if the device runs HarmonyOS, EMUI, or Magic UI. Typically found under Settings > About Phone > Software Information.Affected if The device does not run HarmonyOS, EMUI, or Magic UI (this vulnerability only affects these Huawei platforms)
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Check HarmonyOS versionNavigate to Settings > About Phone > Software Information and locate the HarmonyOS version number.Affected if The HarmonyOS version is less than 2.0 (any version number below 2.0)
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Check EMUI versionNavigate to Settings > About Phone and find the EMUI version displayed.Affected if The EMUI version is exactly 11.0.0 or exactly 12.0.0
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Check Magic UI versionNavigate to Settings > About Phone and identify the Magic UI version.Affected if The Magic UI version is exactly 4.0.0
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Verify AOD feature statusGo to Settings > Display > Always-On Display or Settings > Wallpaper and Style > Always-On Display to check if the feature is currently enabled.Affected if The Always-On Display feature is turned on (the vulnerability exists in the AOD module, so it only applies when AOD is active)
The device is affected if it runs HarmonyOS below version 2.0, EMUI version 11.0.0 or 12.0.0, or Magic UI version 4.0.0, and has the Always-On Display feature enabled.
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 data2.0
Apply vendor-provided security patches for affected smartphone models and consider disabling AOD functionality until updates are available.
- Consultation4.0 h
- Implementation8.0 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 $5,600.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-40038 — 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-2021-40038 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
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