CVE-2024-40964 – A null pointer dereference vulnerability exists... (How to Fix)

Q: What is the severity of CVE-2024-40964?

CVE-2024-40964 has a CVSS score of 5.5 (MEDIUM). A null pointer dereference vulnerability exists in the Linux kernel's ALSA HDA driver for CS35L41 audio codecs. When a device with index 0 is unbound, the cs35l41_hda_unbind() function may dereference a null pointer, potentially causing a kernel panic or system crash. This affects Linux systems using the affected kernel versions with CS35L41 audio hardware.

📋 TL;DR

A null pointer dereference vulnerability exists in the Linux kernel's ALSA HDA driver for CS35L41 audio codecs. When a device with index 0 is unbound, the cs35l41_hda_unbind() function may dereference a null pointer, potentially causing a kernel panic or system crash. This affects Linux systems using the affected kernel versions with CS35L41 audio hardware.

💻 Affected Systems

Products:

Linux kernel

Versions: Specific affected kernel versions not specified in CVE, but patches exist in stable kernel trees.

Operating Systems: Linux distributions using vulnerable kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects systems with CS35L41 audio codec hardware and ALSA HDA driver loaded.

📦 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 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

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

🟠

Likely Case

System instability or crash when audio devices are removed or reconfigured, causing temporary denial of service.

🟢

If Mitigated

Minor system disruption during audio device management operations.

🌐 Internet-Facing: LOW - Requires local access or specific audio device manipulation.

🏢 Internal Only: MEDIUM - Could be exploited by local users or through automated device management.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires local access and ability to trigger audio device unbinding operations.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Patches available in stable kernel trees (commits: 19be722369c3, 6386682cdc8b, ff27bd8e1788)

Vendor Advisory: https://git.kernel.org/stable/c/19be722369c347f3af1c5848e303980ed040b819

Restart Required: Yes

Instructions:

1. Update to patched kernel version from your distribution. 2. Rebuild kernel if using custom kernel. 3. Reboot system after update.

🔧 Temporary Workarounds

Disable CS35L41 audio driver

linux

Prevent loading of vulnerable driver module

echo 'blacklist snd_hda_codec_cs35l41' >> /etc/modprobe.d/blacklist.conf
rmmod snd_hda_codec_cs35l41

🧯 If You Can't Patch

Restrict local user access to audio device management operations.
Monitor system logs for kernel panic events related to audio drivers.

🔍 How to Verify

Check if Vulnerable:

Check if CS35L41 driver is loaded: lsmod | grep cs35l41

Check Version:

uname -r

Verify Fix Applied:

Check kernel version includes patched commits or verify driver version.

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages in /var/log/kern.log or dmesg
Audio driver crash logs

Network Indicators:

None - local vulnerability

SIEM Query:

source="kernel" AND ("panic" OR "Oops") AND "cs35l41"

📊 Metadata

CVE ID: CVE-2024-40964

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 21, 2024

🔗 References

📤 Share & Export

📄 Export Markdown 📋 Export JSON

🔗 Related Vulnerabilities

If you're affected by CVE-2024-40964, you might also want to check these: