CVE-2022-50317 – This is a null pointer dereference vulnerabilit... (How to Fix)

Q: What is the severity of CVE-2022-50317?

CVE-2022-50317 has a CVSS score of 5.5 (MEDIUM). This is a null pointer dereference vulnerability in the Linux kernel's drm/bridge driver for Megachips display bridges. It allows local attackers to cause a kernel panic (denial of service) when removing the affected driver module. Systems using Linux kernels with the vulnerable driver are affected.

📋 TL;DR

This is a null pointer dereference vulnerability in the Linux kernel's drm/bridge driver for Megachips display bridges. It allows local attackers to cause a kernel panic (denial of service) when removing the affected driver module. Systems using Linux kernels with the vulnerable driver are affected.

💻 Affected Systems

Products:

Linux kernel with megachips_stdpxxxx_ge_b850v3_fw driver

Versions: Linux kernel versions before fixes in stable releases

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects systems using the specific Megachips display bridge hardware

📦 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 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Local attacker causes kernel panic leading to system crash and denial of service

🟠

Likely Case

System crash during driver module removal, requiring reboot

🟢

If Mitigated

No impact with proper kernel hardening and module loading restrictions

🌐 Internet-Facing: LOW - Requires local access to trigger

🏢 Internal Only: MEDIUM - Local users or processes could trigger system crashes

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires local access and ability to remove kernel modules

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Linux kernel stable releases containing commit 1daf69228e310938177119c4eadcd30fc75c81e0

Vendor Advisory: https://git.kernel.org/stable/c/1daf69228e310938177119c4eadcd30fc75c81e0

Restart Required: No

Instructions:

1. Update Linux kernel to patched version from your distribution. 2. For custom kernels, apply the fix commit. 3. Rebuild and install kernel if needed.

🔧 Temporary Workarounds

Disable vulnerable driver

all

Prevent loading of the megachips_stdpxxxx_ge_b850v3_fw kernel module

echo 'blacklist megachips_stdpxxxx_ge_b850v3_fw' >> /etc/modprobe.d/blacklist.conf
rmmod megachips_stdpxxxx_ge_b850v3_fw

🧯 If You Can't Patch

Restrict module loading permissions to prevent unauthorized users from removing modules
Implement kernel hardening features like SELinux/AppArmor to restrict module operations

🔍 How to Verify

Check if Vulnerable:

Check if megachips_stdpxxxx_ge_b850v3_fw module is loaded: lsmod | grep megachips

Check Version:

uname -r

Verify Fix Applied:

Check kernel version includes fix commit or is newer than patched releases

📡 Detection & Monitoring

Log Indicators:

Kernel panic logs with 'null-ptr-deref' or 'general protection fault' during module removal
System crash/reboot events

Network Indicators:

None - local vulnerability only

SIEM Query:

kernel: "null-ptr-deref" OR "general protection fault" AND "megachips" OR "stdp"

📊 Metadata

CVE ID: CVE-2022-50317

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

EPSS Score: 0.01% exploit probability (1.2th percentile)

Published: September 15, 2025

Last Updated: December 4, 2025

🔗 References

📤 Share & Export

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🔗 Related Vulnerabilities

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