CVE-2024-40960 – A NULL pointer dereference vulnerability in the... (How to Fix)

Q: What is the severity of CVE-2024-40960?

CVE-2024-40960 has a CVSS score of 5.5 (MEDIUM). A NULL pointer dereference vulnerability in the Linux kernel's IPv6 routing subsystem allows local attackers to cause a kernel panic (denial of service). This affects Linux systems with IPv6 enabled, potentially leading to system crashes.

📋 TL;DR

A NULL pointer dereference vulnerability in the Linux kernel's IPv6 routing subsystem allows local attackers to cause a kernel panic (denial of service). This affects Linux systems with IPv6 enabled, potentially leading to system crashes.

💻 Affected Systems

Products:

Linux Kernel

Versions: Specific affected versions not explicitly stated in CVE, but references indicate fixes in stable kernel trees. Likely affects multiple 6.x kernel versions before fixes.

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Requires IPv6 to be enabled and configured. Systems without IPv6 or with IPv6 disabled 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 →

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 console access to reboot.

🟠

Likely Case

Local denial of service through kernel crash, disrupting services running on the affected system.

🟢

If Mitigated

Minimal impact if systems are patched or have IPv6 disabled.

🌐 Internet-Facing: LOW - Requires local access to trigger, not remotely exploitable over network.

🏢 Internal Only: MEDIUM - Local users or compromised accounts could crash the kernel, affecting system availability.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: LOW - Simple local trigger of NULL dereference.

Discovered by syzbot fuzzer. Exploitation requires local access to trigger the vulnerable code path in rt6_probe().

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Multiple stable kernel commits referenced (1ed9849fdf9a, 51ee2f7c3079, 569c9d9ea664, 6eed6d3cd19f, 73e7c8ca6ad7)

Vendor Advisory: https://git.kernel.org/stable/c/1ed9849fdf9a1a617129346b11d2094ca26828dc

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version from your distribution. 2. For custom kernels, apply commits from stable tree. 3. Reboot system after kernel update.

🔧 Temporary Workarounds

Disable IPv6

linux

Completely disable IPv6 networking to prevent vulnerable code path execution.

echo 'net.ipv6.conf.all.disable_ipv6 = 1' >> /etc/sysctl.conf
echo 'net.ipv6.conf.default.disable_ipv6 = 1' >> /etc/sysctl.conf
sysctl -p

🧯 If You Can't Patch

Restrict local user access to prevent malicious users from triggering the vulnerability
Implement strict monitoring for kernel panics and system crashes

🔍 How to Verify

Check if Vulnerable:

Check kernel version and if IPv6 is enabled: 'uname -r' and 'ip -6 addr show'

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version is updated beyond patched commits and system remains stable during IPv6 operations.

📡 Detection & Monitoring

Log Indicators:

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

Network Indicators:

Unusual local IPv6 routing activity preceding crashes

SIEM Query:

source="kernel" AND "NULL pointer dereference" AND "rt6_probe" OR "general protection fault"

📊 Metadata

CVE ID: CVE-2024-40960

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: July 12, 2024

Last Updated: November 3, 2025

🔗 References

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🔗 Related Vulnerabilities

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