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ZephyrOperating system · Zephyrproject

CVE-2023-4424

HIGH · 8.8 CVSS v3.1 Published 2023-11-21
Fix available
A fix is available. Upgrade to after 3.4.0 or later.
See remediation →
93/100
Remediation priority · Urgent
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
An malicious BLE device can cause buffer overflow by sending malformed advertising packet BLE device using Zephyr OS, leading to DoS or potential RCE on the victim BLE device.

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 confidence

A buffer overflow vulnerability exists in the Zephyr OS BLE stack where a malicious BLE device can send malformed advertising packets to trigger a buffer overflow in the victim's BLE advertising packet handling code. This can result in denial of service or potential remote code execution on the affected device.

MitigationUpdate Zephyr OS to the latest version containing the security fix. If patching is not immediately feasible, restrict BLE connectivity to trusted devices and monitor for unusual BLE activity.

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
ZephyrOperating system
Affected:<= 3.4.0

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 if the device runs Zephyr OS
    Check system information files such as /proc/version, dmesg output, or boot logs for 'Zephyr' or check build artifacts (CMakeLists.txt, west.yml) in the firmware source for Zephyr project references
    Affected if The system or firmware is built on the Zephyr OS kernel
  2. Determine the installed Zephyr version
    Locate the version string in build configuration files (zephyr/version.h), kernel headers, or firmware metadata. Run 'west boards' or inspect the Zephyr manifest (yaml) file in the build system
    Affected if The Zephyr version is 3.4.0 or lower
  3. Verify BLE subsystem is enabled
    Examine the kernel or firmware configuration for CONFIG_BT=y, CONFIG_BLUETOOTH=y, or check if the Bluetooth subsystem is loaded/running (systemctl status bluetooth, btmon, or hcitool dev)
    Affected if CONFIG_BT or CONFIG_BLUETOOTH is enabled in the build configuration or Bluetooth is functional on the device
  4. Confirm BLE advertising functionality is in use
    Check for CONFIG_BT_ADV*=y in kernel config, or use btmon/hcitool to observe active advertising instances (hcitool -i hci0 leadv), or review application code for bt_adv_start API calls
    Affected if BLE advertising is configured or active on the device

The environment is affected if the device runs Zephyr OS version 3.4.0 or lower with the BLE stack and advertising feature enabled, making it vulnerable to malformed advertising 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.

dbcve · scoped
Upgrade available Upgrade to a release after 3.4.0
Interim mitigation

Update Zephyr OS to the latest version containing the security fix. If patching is not immediately feasible, restrict BLE connectivity to trusted devices and monitor for unusual BLE activity.

Recommended fix Moderate confidence

Zephyr > 3.4.0 (check Zephyr security advisories for the exact fixed release)

  1. 1. Identify the specific Zephyr RTOS version currently deployed in your BLE device firmware
  2. 2. Update Zephyr to a version newer than 3.4.0 that includes the security fix for this vulnerability
  3. 3. Rebuild the BLE host stack and firmware with the updated Zephyr version
  4. 4. Flash the updated firmware to the affected BLE devices
  5. 5. Verify BLE functionality and confirm the patch is applied by testing with malformed advertising packets
Caveat Review Zephyr release notes between 3.4.0 and the target version for any breaking changes to BLE stack APIs or configuration

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Zephyr Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing10.0 h
  • Review / QA5.0 h
33.0 hours of engineering $5,760
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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-2023-4424 in production — separate from our analysis above.

No notes yet

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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
  • 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
  • No spam, self-promotion, credentials, or personal data