CVE-2023-53667 – A kernel memory corruption vulnerability in the... (How to Fix)

Q: What is the severity of CVE-2023-53667?

CVE-2023-53667 has a CVSS score of 5.5 (MEDIUM). A kernel memory corruption vulnerability in the Linux kernel's CDC NCM USB network driver allows for potential denial-of-service attacks when handling malformed network packets. Systems using affected Linux kernel versions with CDC NCM USB network adapters are vulnerable. The vulnerability can cause kernel panics leading to system crashes.

📋 TL;DR

A kernel memory corruption vulnerability in the Linux kernel's CDC NCM USB network driver allows for potential denial-of-service attacks when handling malformed network packets. Systems using affected Linux kernel versions with CDC NCM USB network adapters are vulnerable. The vulnerability can cause kernel panics leading to system crashes.

💻 Affected Systems

Products:

Linux kernel

Versions: Multiple stable kernel versions before fixes were applied (specific versions in git commits provided)

Operating Systems: Linux distributions using vulnerable kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects systems using CDC NCM USB network adapters. Most systems without these specific USB network interfaces are not vulnerable.

📦 What is this software?

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

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Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

Linux Kernel by Linux

The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...

Learn more about Linux Kernel →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Kernel panic leading to complete system crash and denial-of-service, requiring physical or remote reboot to restore functionality.

🟠

Likely Case

System crash when processing malformed network packets from untrusted sources, causing temporary service disruption.

🟢

If Mitigated

No impact if patched or if CDC NCM USB network adapters are not in use.

🌐 Internet-Facing: MEDIUM - Systems with CDC NCM USB network interfaces exposed to untrusted networks could be crashed by crafted packets.

🏢 Internal Only: LOW - Requires local network access or malicious internal actor to exploit.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires ability to send crafted network packets to a system with vulnerable CDC NCM USB network adapter. No authentication bypass required but requires network access to the interface.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Multiple kernel versions with fixes (see git commit references in CVE description)

Vendor Advisory: https://git.kernel.org/stable/c/2334ff0b343ba6ba7a6c0586fcc83992bbbc1776

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version from your distribution's repositories. 2. Reboot system to load new kernel. 3. Verify kernel version after reboot.

🔧 Temporary Workarounds

Disable CDC NCM USB network interfaces

Linux

Prevent use of vulnerable CDC NCM USB network adapters by disabling or blacklisting the driver

echo 'blacklist cdc_ncm' >> /etc/modprobe.d/blacklist-cdc_ncm.conf
update-initramfs -u
reboot

🧯 If You Can't Patch

Disconnect or avoid using CDC NCM USB network adapters
Implement network segmentation to isolate systems with CDC NCM interfaces from untrusted networks

🔍 How to Verify

Check if Vulnerable:

Check if CDC NCM module is loaded: lsmod | grep cdc_ncm AND check kernel version against affected ranges

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version is patched AND test CDC NCM functionality remains operational

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages mentioning 'skb_over_panic' or 'cdc_ncm'
System crash/reboot logs without clear cause

Network Indicators:

Unusual traffic patterns to systems with CDC NCM interfaces
Multiple connection attempts to USB network interface ports

SIEM Query:

source="kernel" AND ("skb_over_panic" OR "cdc_ncm" OR "kernel BUG at net/core/skbuff.c")

📊 Metadata

CVE ID: CVE-2023-53667

CVSS v3 Score: 5.5 (MEDIUM)

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CWE: CWE-476

EPSS Score: 0.02% exploit probability (5.5th percentile)

Published: October 7, 2025

Last Updated: February 26, 2026

🔗 References

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🔗 Related Vulnerabilities

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