dbcve.org
Linux KernelOperating system · Linux

CVE-2023-2166

MEDIUM · 5.5 CVSS v3.1 Published 2023-04-19
Fix available
A fix is available. Upgrade to 6.1 or later.
See remediation →
57/100
Remediation priority · Elevated
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
A null pointer dereference issue was found in can protocol in net/can/af_can.c in the Linux before Linux. ml_priv may not be initialized in the receive path of CAN frames. A local user could use this flaw to crash the system or potentially cause a denial of service.

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 null pointer dereference vulnerability exists in the Linux kernel's CAN (Controller Area Network) protocol implementation in net/can/af_can.c. The issue occurs in the receive path where ml_priv (likely a per-socket private data pointer) may not be properly initialized before being accessed, allowing a local user to trigger a kernel NULL pointer dereference and cause a denial of service.

MitigationApply the Linux kernel patch that ensures ml_priv is properly initialized in the CAN frame receive path. Organizations should update to kernels that have incorporated the fix and test CAN functionality after applying the update.

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:< 6.1= 6.1

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
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/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. Check the running kernel version
    Run 'uname -r' or 'uname -a' to obtain the kernel version
    Affected if The kernel version is 6.1.x or lower than 6.1 (e.g., 5.x series)
  2. Verify CAN kernel modules are loaded
    Run 'lsmod | grep -E "^can|^af_can"' to check if CAN-related kernel modules are loaded
    Affected if CAN modules (can, af_can, can_raw, can_bcm) are loaded and in use
  3. Check for active CAN network interfaces
    Run 'ip link show' or 'ifconfig -a' and look for interfaces named 'can0', 'vcan0', or similar CAN interfaces
    Affected if CAN interfaces exist and are configured (indicates CAN receive path is active)
  4. Inspect the af_can.c source or module
    Check /usr/src/linux/net/can/af_can.c or run 'modinfo af_can' to see the module version and build date
    Affected if The source file or module predates the CVE fix (patch addresses ml_priv initialization)
  5. Review kernel logs for CAN-related NULL pointer errors
    Run 'dmesg | grep -i can' or check /var/log/kern.log for NULL pointer dereference errors related to CAN
    Affected if Kernel logs show NULL pointer dereference errors in can_rcv or af_can code paths

A system is affected if it runs a Linux kernel version 6.1 or lower AND has CAN functionality enabled (modules loaded or CAN interfaces configured), as this creates the conditions for the uninitialized ml_priv to be dereferenced in the CAN receive path.

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 6.1 or later
Fixed in 6.1
Interim mitigation

Apply the Linux kernel patch that ensures ml_priv is properly initialized in the CAN frame receive path. Organizations should update to kernels that have incorporated the fix and test CAN functionality after applying the update.

Recommended fix Moderate confidence

Linux kernel 6.2 or later (stable/lts version)

  1. Upgrade the Linux kernel to version 6.2 or later to resolve the NULL pointer dereference in net/can/af_can.c
  2. After upgrading, reboot the system to load the fixed kernel
  3. Verify the kernel version after reboot using 'uname -r'
Caveat Kernel upgrade may require recompilation of third-party kernel modules; ensure driver compatibility with the new kernel version

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

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing5.0 h
  • Review / QA3.0 h
17.0 hours of engineering $2,970
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,752.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2023-2166 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2023-2166 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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