CVE-2024-35851 – A NULL pointer dereference vulnerability in the... (How to Fix)

Q: What is the severity of CVE-2024-35851?

CVE-2024-35851 has a CVSS score of 5.5 (MEDIUM). A NULL pointer dereference vulnerability in the Linux kernel's Bluetooth Qualcomm Atheros (qca) driver allows local attackers to cause a kernel panic (system crash) by triggering suspend operations on non-serdev Bluetooth controllers. This affects Linux systems with Qualcomm ROME Bluetooth controllers registered via the Bluetooth line discipline. The vulnerability requires local access to exploit.

📋 TL;DR

A NULL pointer dereference vulnerability in the Linux kernel's Bluetooth Qualcomm Atheros (qca) driver allows local attackers to cause a kernel panic (system crash) by triggering suspend operations on non-serdev Bluetooth controllers. This affects Linux systems with Qualcomm ROME Bluetooth controllers registered via the Bluetooth line discipline. The vulnerability requires local access to exploit.

💻 Affected Systems

Products:

Linux kernel

Versions: Linux kernel versions before the fix commits (specifically pre-6.2 kernels affected by this specific crash, but check all stable branches)

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ✅ No

Notes: Only affects systems with Qualcomm ROME Bluetooth controllers registered via Bluetooth line discipline (non-serdev configuration). Most systems use serdev, making this a less common configuration.

📦 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 →

⚠️ 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

System crash when suspend/resume operations are triggered on affected Bluetooth configurations, causing temporary denial of service.

🟢

If Mitigated

No impact if patched or if system doesn't use affected Bluetooth controller configurations.

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

🏢 Internal Only: MEDIUM - Local attackers or malicious processes could crash the system, but requires specific Bluetooth configuration.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: NO

Unauthenticated Exploit: ✅ No

Complexity: LOW

Exploitation requires local access and ability to trigger suspend operations on affected Bluetooth configuration. No authentication bypass needed beyond local access.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Fixed in kernel commits: 52f9041deaca3fc5c40ef3b9cb943993ec7d2489, 6b47cdeb786c38e4174319218db3fa6d7b4bba88, 73e87c0a49fda31d7b589edccf4c72e924411371, b64092d2f108f0cd1d7fd7e176f5fb2a67a2f189, e60502b907be350c518819297b565007a94c706d

Vendor Advisory: https://git.kernel.org/stable/c/52f9041deaca3fc5c40ef3b9cb943993ec7d2489

Restart Required: Yes

Instructions:

1. Update Linux kernel to version containing the fix commits. 2. Check your distribution's security advisories for backported patches. 3. Reboot system after kernel update.

🔧 Temporary Workarounds

Disable affected Bluetooth configuration

linux

Prevent Qualcomm ROME controllers from being registered via Bluetooth line discipline

# Check if using affected configuration
dmesg | grep -i 'qca'
# Consider disabling Bluetooth if not needed
systemctl disable bluetooth
systemctl stop bluetooth

🧯 If You Can't Patch

Restrict local access to prevent malicious users from triggering suspend operations
Monitor system logs for kernel panic events related to Bluetooth suspend operations

🔍 How to Verify

Check if Vulnerable:

Check kernel version and if using Qualcomm ROME Bluetooth: uname -r and dmesg | grep -i 'qca'

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version includes fix commits or check with distribution's security update verification tools

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages in /var/log/kern.log or dmesg
Bluetooth suspend/resume failure logs
NULL pointer dereference errors mentioning qca or Bluetooth

Network Indicators:

None - this is a local kernel vulnerability

SIEM Query:

source="kernel" AND ("NULL pointer" OR "kernel panic" OR "qca")

📊 Metadata

CVE ID: CVE-2024-35851

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: May 17, 2024

Last Updated: December 30, 2024

🔗 References

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🔗 Related Vulnerabilities

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