CVE-2021-3430

Device crash via repeated Bluetooth parameter requests

Published Jun 28, 2022 · Updated Sep 16, 2024

Reachable assertion in Zephyr RTOS 1.14 through 2.5.x allows physically proximate attackers to crash Bluetooth-enabled devices. The Bluetooth controller's Connection Parameter Request procedure asserts when it receives a repeated LL_CONNECTION_PARAM_REQ during an active transaction instead of ignoring the protocol violation. Bluetooth LE radio proximity is required, but no credentials or user action are needed; the assertion interrupts device availability without exposing or modifying data.

CVSS severity6.5
Medium
EPSS probability0.89%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reachable assertion in Zephyr RTOS 1.14 through 2.5.x allows physically proximate attackers to crash Bluetooth-enabled devices. The Bluetooth controller's Connection Parameter Request procedure asserts when it receives a repeated LL_CONNECTION_PARAM_REQ during an active transaction instead of ignoring the protocol violation. Bluetooth LE radio proximity is required, but no credentials or user action are needed; the assertion interrupts device availability without exposing or modifying data.

The record

CVE
CVE-2021-3430
Published
Jun 28, 2022
Updated
Sep 16, 2024
Vendor
Zephyr Project
Product
Zephyr RTOS
Classifications
CWE-617, T1499
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 28, 2022CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 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?

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  1. Affected versionversion=v1.14.0 <unspecified
  2. Affected versionversion=v2.5.0 <unspecified

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Zephyr Project · Zephyr RTOSversion=v1.14.0 <unspecified; version=v2.5.0 <unspecified

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
6.5Zephyr ProjectCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5NIST NVDCVSS:3.1/AV:N/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-617Reachable Assertion
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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