CVE-2023-52861 – A NULL pointer dereference vulnerability in the... (How to Fix)

Q: What is the severity of CVE-2023-52861?

CVE-2023-52861 has a CVSS score of 6.2 (MEDIUM). A NULL pointer dereference vulnerability in the Linux kernel's IT66121 DisplayPort bridge driver allows local attackers to cause a kernel panic when no monitor is connected and the sound card is accessed. This affects Linux systems using the IT66121 bridge hardware. The vulnerability requires local access to trigger.

📋 TL;DR

A NULL pointer dereference vulnerability in the Linux kernel's IT66121 DisplayPort bridge driver allows local attackers to cause a kernel panic when no monitor is connected and the sound card is accessed. This affects Linux systems using the IT66121 bridge hardware. The vulnerability requires local access to trigger.

💻 Affected Systems

Products:

Linux kernel with IT66121 DisplayPort bridge driver

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

Operating Systems: Linux distributions using vulnerable kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects systems with IT66121 bridge hardware and when no monitor is connected while sound card is accessed.

📦 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 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Kernel panic leading to system crash and denial of service, potentially causing data loss or service disruption.

🟠

Likely Case

System crash or instability when userspace applications attempt to access sound functionality without a connected monitor.

🟢

If Mitigated

Minor service interruption that requires system reboot to recover.

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

🏢 Internal Only: MEDIUM - Local users or processes can trigger system crashes, affecting availability.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: NO

Unauthenticated Exploit: ✅ No

Complexity: LOW

Exploitation requires local access and specific hardware configuration. No public exploits known.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Fixed in kernel commits: 1374561a7cbc9a000b77bb0473bb2c19daf18d86, 1669d7b21a664aa531856ce85b01359a376baebc, 2c80c4f0d2845645f41cbb7c9304c8efbdbd4331, d0375f6858c4ff7244b62b02eb5e93428e1916cd

Vendor Advisory: https://git.kernel.org/stable/c/1374561a7cbc9a000b77bb0473bb2c19daf18d86

Restart Required: Yes

Instructions:

1. Update Linux kernel to version containing the fix commits. 2. Check distribution-specific security advisories. 3. Reboot system after kernel update.

🔧 Temporary Workarounds

Disable IT66121 bridge module

linux

Prevent loading of the vulnerable driver module

echo 'blacklist it66121' >> /etc/modprobe.d/blacklist-it66121.conf
rmmod it66121

Ensure monitor connection

all

Keep a monitor connected to systems with IT66121 hardware

🧯 If You Can't Patch

Restrict local user access to systems with IT66121 hardware
Implement monitoring for kernel panic events and rapid recovery procedures

🔍 How to Verify

Check if Vulnerable:

Check if IT66121 module is loaded: lsmod | grep it66121 AND check kernel version against patched versions

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version includes fix commits and IT66121 module loads without issues

📡 Detection & Monitoring

Log Indicators:

Kernel panic messages in /var/log/kern.log or dmesg
NULL pointer dereference errors mentioning it66121

Network Indicators:

None - local vulnerability only

SIEM Query:

source="kernel" AND ("NULL pointer dereference" OR "kernel panic") AND "it66121"

📊 Metadata

CVE ID: CVE-2023-52861

CVSS v3 Score: 6.2 (MEDIUM)

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

CWE: CWE-476

Published: May 21, 2024

Last Updated: April 2, 2025

🔗 References

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🔗 Related Vulnerabilities

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