CVE-2021-31787
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 · uneditedThe Bluetooth Classic implementation on Actions ATS2815 chipsets does not properly handle the reception of continuous unsolicited LMP responses, allowing attackers in radio range to trigger a denial of service and shutdown of a device by flooding the target device with LMP_features_res packets.
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 confidenceThe Actions ATS2815 chipset's Bluetooth Classic implementation lacks proper handling for continuous unsolicited LMP (Link Management Protocol) responses. An attacker within radio range can flood the target device with LMP_features_res packets, causing the device to become unresponsive and shut down due to resource exhaustion.
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 dataall versionsall versionsall versionsall versionsall versionsCVSS 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
- Adjacent
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/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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Identify the Bluetooth chipset in useCheck device documentation, system information, or hardware specifications for the Bluetooth controller model. Look for references to Actions Semi ATS2815, ATS2819, ATS2819p, ATS2819s, or ATS2819t chipsets.Affected if The device uses any of the Actions Semi ATS28xx series chipsets listed in the affected products.
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Determine the firmware versionAccess the device firmware or system settings to retrieve the Bluetooth chipset firmware version. This is typically found in about/system settings, deviceinfo logs, or by querying the Bluetooth controller directly if supported.Affected if Any firmware version is installed on the affected chipset, since all versions are vulnerable.
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Verify Bluetooth Classic is enabledCheck the device Bluetooth settings or configuration to confirm Bluetooth Classic (BR/EDR) is actively enabled, not just Bluetooth Low Energy. The vulnerability exploits LMP (Link Management Protocol) which is specific to Bluetooth Classic.Affected if Bluetooth Classic (BR/EDR) is enabled and the device is within radio range of potential attackers.
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Assess device Bluetooth exposureReview whether the device Bluetooth is discoverable, connectable, or has reduced visibility settings applied. Check if the device is used in public or uncontrolled environments.Affected if The device Bluetooth is publicly accessible without range limiting or access controls.
A user is affected if their device contains any Actions Semi ATS28xx chipset (2815, 2819, 2819p, 2819s, 2819t) with Bluetooth Classic enabled, as all firmware versions of these chipsets are vulnerable to LMP-based resource exhaustion attacks.
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 vendor firmware updates when available; otherwise, limit device Bluetooth exposure by reducing radio range visibility and monitoring for unusual LMP traffic patterns.
- Consultation4.0 h
- Implementation2.0 h
- Testing8.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-31787 — 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-2021-31787 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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