CVE-2024-38637 – This CVE describes a NULL pointer dereference v... (How to Fix)

Q: What is the severity of CVE-2024-38637?

CVE-2024-38637 has a CVSS score of 5.5 (MEDIUM). This CVE describes a NULL pointer dereference vulnerability in the Linux kernel's Greybus lights subsystem. If exploited, it could cause a kernel panic or system crash, affecting systems using Greybus hardware interfaces (typically embedded/IoT devices). The vulnerability occurs when the system fails to validate return values from the get_channel_from_mode function before using them.

📋 TL;DR

This CVE describes a NULL pointer dereference vulnerability in the Linux kernel's Greybus lights subsystem. If exploited, it could cause a kernel panic or system crash, affecting systems using Greybus hardware interfaces (typically embedded/IoT devices). The vulnerability occurs when the system fails to validate return values from the get_channel_from_mode function before using them.

💻 Affected Systems

Products:

Linux kernel with Greybus subsystem enabled

Versions: Linux kernel versions before the fix commits (specific versions vary by distribution)

Operating Systems: Linux distributions with vulnerable kernel versions

Default Config Vulnerable: ✅ No

Notes: Only vulnerable if Greybus subsystem is compiled/enabled and specific hardware with Greybus lighting interfaces is present. Most desktop/server systems are not affected.

📦 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...

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 system crash and denial of service, potentially requiring physical restart of affected devices.

🟠

Likely Case

System instability or crash when specific Greybus lighting operations are performed, resulting in temporary denial of service.

🟢

If Mitigated

No impact if the vulnerable code path isn't triggered or if proper input validation prevents the condition.

🌐 Internet-Facing: LOW - Greybus interfaces are typically internal hardware buses, not directly internet-accessible.

🏢 Internal Only: MEDIUM - Requires local access or ability to trigger specific Greybus operations on affected systems.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: NO

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires ability to trigger specific Greybus lighting operations. No known public exploits exist.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Fixed in kernel commits: 330f6bcdcef03f70f81db5f2ed6747af656a09f2, 518e2c46b5dbce40b1aa0100001d03c3ceaa7d38, 895cdd9aa9546523df839f9cc1488a0ecc1e0731, 8f4a76d477f0cc3c54d512f07f6f88c8e1c1e07b, 9b41a9b9c8be8c552f10633453fdb509e83b66f8

Vendor Advisory: https://git.kernel.org/stable/c/330f6bcdcef03f70f81db5f2ed6747af656a09f2

Restart Required: Yes

Instructions:

1. Update Linux kernel to version containing the fix commits. 2. For distributions: Use package manager (apt/yum/dnf) to update kernel package. 3. Reboot system to load new kernel.

🔧 Temporary Workarounds

Disable Greybus subsystem

linux

Remove or disable Greybus kernel module if not required

modprobe -r gb-lights
echo 'blacklist gb-lights' >> /etc/modprobe.d/blacklist.conf

🧯 If You Can't Patch

Restrict access to systems with Greybus hardware to trusted users only
Monitor system logs for kernel panic/crash events related to Greybus operations

🔍 How to Verify

Check if Vulnerable:

Check if Greybus lights module is loaded: lsmod | grep gb-lights AND check kernel version against patched versions

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version includes fix commits and Greybus module loads without issues

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages
NULL pointer dereference errors in dmesg/kernel logs
System crash/reboot events

Network Indicators:

None - this is a local kernel vulnerability

SIEM Query:

source="kernel" AND ("NULL pointer dereference" OR "kernel panic" OR "gb-lights")

📊 Metadata

CVE ID: CVE-2024-38637

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

Published: June 21, 2024

Last Updated: November 4, 2025

🔗 References

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🔗 Related Vulnerabilities

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