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Mi True Wireless Earbuds Basic 2 FirmwareOperating system · Mi

CVE-2021-31610

MEDIUM · 6.5 CVSS v3.1 Published 2021-09-07
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
70/100
Remediation priority · Elevated
No privileges Zero-click

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 · unedited
The Bluetooth Classic implementation on AB32VG1 devices does not properly handle the reception of continuous unsolicited LMP responses, allowing attackers in radio range to trigger a denial of service (either restart or deadlock the device) by flooding a device with LMP_AU_rand data.

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 confidence

The AB32VG1 Bluetooth Classic implementation lacks proper input validation for unsolicited LMP (Link Manager Protocol) responses. An attacker within radio range can flood the device with continuous LMP_AU_rand packets, causing either device restart or deadlock (unresponsive state). The vulnerability stems from the device processing unexpected LMP authentication requests without rate limiting or proper state management.

MitigationImplement LMP packet validation to reject unsolicited responses, add rate limiting on LMP processing, and improve the Bluetooth stack state machine to handle unexpected LMP sequences without crashing or freezing. Firmware update from the vendor would be required.

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
Mi True Wireless Earbuds Basic 2 FirmwareOperating system
Affected:all versions
Ab5376t FirmwareOperating system
Affected:all versions
Bt8896a FirmwareOperating system
Affected:all versions

CVSS 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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify the Bluetooth device model and firmware version
    Check your device's packaging, companion app settings, or system Bluetooth information for the firmware version. For Mi True Wireless Earbuds Basic 2, use the Xiaomi Mi True Wireless Earbuds app or your device Bluetooth settings to view firmware info.
    Affected if The firmware version corresponds to Mi Mi True Wireless Earbuds Basic 2, Bluetrum Ab5376t, or Bluetrum Bt8896a (all versions are affected)
  2. Identify the Bluetooth chip manufacturer and model
    Consult your device documentation, product specifications, or use Bluetooth diagnostic tools (like android Bluetooth HCI snoop logs or Bluetooth profiler apps) to identify the Bluetooth controller chipset.
    Affected if The device uses a Bluetrum Ab5376t or Bt8896a Bluetooth chip (these chips have no version-specific fix)
  3. Verify if device is actively accepting Bluetooth connections
    Ensure Bluetooth is enabled and the device is in pairing or connected mode. The vulnerability is triggered by LMP packets exchanged during Bluetooth proximity, so any active Bluetooth discoverable or connected state exposes the device.
    Affected if The device has Bluetooth enabled and is within radio range of potential attackers - the flaw is triggered by processing unsolicited LMP responses without user interaction required

You are affected if your Bluetooth earbuds or device uses Mi True Wireless Earbuds Basic 2 firmware or contains a Bluetrum Ab5376t or Bt8896a chip - all versions of these products lack proper LMP input validation and are vulnerable to denial-of-service from nearby attackers flooding LMP_AU_rand packets.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement LMP packet validation to reject unsolicited responses, add rate limiting on LMP processing, and improve the Bluetooth stack state machine to handle unexpected LMP sequences without crashing or freezing. Firmware update from the vendor would be required.

Fix this in Mi True Wireless Earbuds Basic 2 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation16.0 h
  • Testing12.0 h
  • Review / QA6.0 h
38.0 hours of engineering $6,560
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-31610 in production — separate from our analysis above.

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What this is

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.

What belongs here
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  • Version or environment caveats, and links to real fixes
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