CVE-2021-34149
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 the Texas Instruments CC256XCQFN-EM does not properly handle the reception of continuous LMP_AU_Rand packets, allowing attackers in radio range to trigger a denial of service (deadlock) of the device by flooding it with LMP_AU_Rand packets after the paging procedure.
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 Texas Instruments CC256XCQFN-EM Bluetooth chip's Classic (BR/EDR) implementation fails to properly handle continuous LMP_AU_Rand (Link Manager Protocol Authentication Random) packets. An attacker within radio range can flood the device with these packets after the paging procedure, causing a deadlock condition that results in denial of service.
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 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 TI CC256XCQFN-EM chip presenceReview hardware specifications, device documentation, or Bill of Materials (BOM) to determine if the Texas Instruments CC256XCQFN-EM Bluetooth chip is installed in the systemAffected if The device uses the TI CC256XCQFN-EM chip for Bluetooth functionality
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Verify Bluetooth Classic (BR/EDR) is enabledCheck system Bluetooth stack configuration or firmware settings to confirm Classic Bluetooth mode is active (not just BLE)Affected if Bluetooth Classic (BR/EDR) is enabled and operational on the device
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Check for Bluetooth deadlock behaviorMonitor Bluetooth subsystem for unexplained freezes or complete unresponsiveness where the Bluetooth interface becomes non-functional after a period of activityAffected if Device exhibits Bluetooth deadlock or total loss of Bluetooth functionality without other hardware failure
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Assess physical radio exposureEvaluate the deployment environment to determine if untrusted attackers could be within Bluetooth radio range to send malicious LMP_AU_Rand packetsAffected if Device is deployed in an area where untrusted individuals could be within radio range and send continuous LMP_AU_Rand packets after paging
A system is affected if it contains the TI CC256XCQFN-EM chip with Bluetooth Classic (BR/EDR) enabled, as this specific hardware/firmware combination is vulnerable to the LMP_AU_Rand packet deadlock flaw in all versions.
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-provided firmware patches from Texas Instruments. If no patch is available, implement network-level controls to limit Bluetooth exposure to trusted devices and consider replacing affected hardware.
- Consultation3.0 h
- Implementation8.0 h
- Testing5.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-34149 — 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-2021-34149 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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