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Linux KernelOperating system · Linux

CVE-2024-21803

HIGH · 7.8 CVSS v3.1 Published 2024-01-30
Fix available
A fix is available. Upgrade to after 6.6.8 or later.
See remediation →
80/100
Remediation priority · High
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
Use After Free vulnerability in Linux Linux kernel kernel on Linux, x86, ARM (bluetooth modules) allows Local Execution of Code. This vulnerability is associated with program files https://gitee.Com/anolis/cloud-kernel/blob/devel-5.10/net/bluetooth/af_bluetooth.C. This issue affects Linux kernel: from v2.6.12-rc2 before v6.8-rc1.

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

Use After Free vulnerability in the Linux kernel's bluetooth subsystem (af_bluetooth.c) allows local attackers to execute arbitrary code. The flaw exists in the bluetooth module handling code and persists from kernel v2.6.12-rc2 through versions before v6.8-rc1.

MitigationUpgrade Linux kernel to v6.8-rc1 or later to obtain the patched version of af_bluetooth.c. For systems that cannot upgrade immediately, consider disabling bluetooth or restricting local access as a compensating control.

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
Linux KernelOperating system
Affected:>= 2.6.12.1, <= 6.6.8= 2.6.12= 6.7

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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/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 the running kernel version
    Run `uname -r` or check `/proc/version` to get the exact kernel version string
    Affected if The kernel version falls within >= 2.6.12.1 and <= 6.6.8, equals 2.6.12, or equals 6.7 (i.e., any version before v6.8-rc1)
  2. Confirm the bluetooth kernel module is loaded
    Run `lsmod | grep bluetooth` or check `/proc/modules` for bluetooth-related modules
    Affected if The bluetooth module or any bluetooth subsystem module (e.g., bluetooth, btusb, bnep, rfcomm) is loaded in memory
  3. Verify bluetooth subsystem is active
    Run `systemctl status bluetooth` (systemd) or check `hciconfig -a` output for active bluetooth interfaces
    Affected if The bluetooth service is running or a bluetooth interface is up (hci0 or similar present)
  4. Check if af_bluetooth socket handling is in use
    Run `ss -ax | grep bluetooth` or inspect `/proc/net/bluetooth/` directory for active bluetooth sockets
    Affected if Any AF_BLUETOOTH family sockets exist (shown as `BT` in ss output or files in /proc/net/bluetooth/)

You are affected if your kernel version is between v2.6.12 and v6.8-rc1 (exclusive) AND the bluetooth subsystem is loaded or active in your environment.

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 6.6.8
Interim mitigation

Upgrade Linux kernel to v6.8-rc1 or later to obtain the patched version of af_bluetooth.c. For systems that cannot upgrade immediately, consider disabling bluetooth or restricting local access as a compensating control.

Recommended fix Moderate confidence

Linux kernel 6.8 or later (e.g., 6.8, 6.9, or current stable)

  1. Identify the current running kernel version using 'uname -r'
  2. Check if your distribution has a patched kernel available for your current major version
  3. If running a distribution kernel (e.g., Red Hat, Ubuntu, Debian), apply the latest distribution-specific security updates which should include the CVE fix
  4. For mainline kernels, upgrade to kernel version 6.8 or later using your distribution's package manager or building from source
  5. Reboot the system into the updated kernel
  6. Verify the kernel version after reboot with 'uname -r' to confirm the update was applied
Caveat Major kernel upgrades may require rebuilding third-party kernel modules (e.g., NVIDIA drivers, VirtualBox); ensure compatible drivers are available for the target kernel version before upgrading

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

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
21.0 hours of engineering $3,680
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Scan for this in your stack

Free · runs locally
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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-2024-21803 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
  • 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