CVE-2021-31785Public exploit

Device deadlock via repeated LMP connection requests

Published Sep 7, 2021 · Updated Aug 3, 2024

Improper locking in Actions ATS2815 and ATS2819 Bluetooth Classic firmware lets attackers deadlock devices via crafted LMP packets. The Bluetooth link manager enters a deadlocked state while processing repeated LMP_host_connection_req packets instead of safely rejecting the flood. An attacker must be within Bluetooth radio range and target a device with no user connected; recovery requires a manual restart to restore Bluetooth communication.

CVSS severity6.5
Medium
EPSS probability0.44%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper locking in Actions ATS2815 and ATS2819 Bluetooth Classic firmware lets attackers deadlock devices via crafted LMP packets. The Bluetooth link manager enters a deadlocked state while processing repeated LMP_host_connection_req packets instead of safely rejecting the flood. An attacker must be within Bluetooth radio range and target a device with no user connected; recovery requires a manual restart to restore Bluetooth communication.

The record

CVE
CVE-2021-31785
Published
Sep 7, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-667, T1499
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 7, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.1NIST National Vulnerability DatabaseAV:A/AC:L/Au:N/C:N/I:N/A:C
6.5NIST National Vulnerability DatabaseCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-667Improper Locking
T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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