CVE-2024-56616 – This vulnerability in the Linux kernel's Displa... (How to Fix)

📋 TL;DR

This vulnerability in the Linux kernel's DisplayPort MST (Multi-Stream Transport) implementation allows memory corruption when processing malformed sideband messages from MST branch devices. It affects systems using DisplayPort MST functionality, potentially leading to kernel crashes or privilege escalation. The issue stems from improper validation of message body length, which can trigger out-of-bounds memory writes.

💻 Affected Systems

Products:

Linux kernel

Versions: Kernel versions with vulnerable drm/dp_mst code (specific affected versions not specified in CVE, but patches available for multiple stable branches)

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects systems with DisplayPort MST functionality enabled/used; requires connection to MST-capable DisplayPort devices

📦 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 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Kernel memory corruption leading to system crash, privilege escalation, or arbitrary code execution in kernel context

🟠

Likely Case

Kernel panic or system instability when processing malformed MST messages from compromised or faulty DisplayPort devices

🟢

If Mitigated

System remains stable with proper kernel patches applied; unpatched systems may experience crashes when connecting to malicious MST devices

🌐 Internet-Facing: LOW - Requires physical or local network access to DisplayPort MST devices

🏢 Internal Only: MEDIUM - Internal attackers with physical access to DisplayPort ports could potentially exploit this

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Exploitation requires ability to send malformed MST sideband messages, typically through physical DisplayPort connection or compromised MST device

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Multiple stable kernel versions with fixes (see references for specific commits)

Vendor Advisory: https://git.kernel.org/stable/c/109f91d8b9335b0f3714ef9920eae5a8b21d56af

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version from your distribution's repositories
2. Apply specific kernel commits if compiling from source
3. Reboot system after kernel update

🔧 Temporary Workarounds

Disable MST functionality

linux

Disable DisplayPort MST support in kernel or avoid using MST-capable devices

echo 'blacklist drm_dp_mst_helper' > /etc/modprobe.d/disable-mst.conf
update-initramfs -u
reboot

🧯 If You Can't Patch

Restrict physical access to DisplayPort ports
Avoid connecting untrusted or unknown DisplayPort MST devices

🔍 How to Verify

Check if Vulnerable:

Check kernel version and verify if drm_dp_mst_topology.c contains the vulnerable length check code

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version is updated to include the fix commits; check dmesg for absence of UBSAN array-index-out-of-bounds errors related to drm_dp_mst_topology

📡 Detection & Monitoring

Log Indicators:

UBSAN: array-index-out-of-bounds in drm_dp_mst_topology.c
memcpy: detected field-spanning write in drm_dp_mst_topology.c
Kernel panic or oops messages related to drm_display_helper

Network Indicators:

Not applicable - local hardware interface vulnerability

SIEM Query:

source="kernel" AND ("drm_dp_mst_topology" OR "UBSAN" OR "array-index-out-of-bounds")

📊 Metadata

CVE ID: CVE-2024-56616

CVSS v3 Score: 7.8 (HIGH)

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

CWE: CWE-129

Published: December 27, 2024

Last Updated: November 3, 2025

🔗 References

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🔗 Related Vulnerabilities

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