CVE-2024-46858 – This is a use-after-free vulnerability in the L... (How to Fix)

Q: What is the severity of CVE-2024-46858?

CVE-2024-46858 has a CVSS score of 7.0 (HIGH). This is a use-after-free vulnerability in the Linux kernel's MPTCP subsystem that occurs due to a race condition in timer deletion. It allows attackers with local access to potentially crash the kernel or execute arbitrary code. All Linux systems using MPTCP with affected kernel versions are vulnerable.

📋 TL;DR

This is a use-after-free vulnerability in the Linux kernel's MPTCP subsystem that occurs due to a race condition in timer deletion. It allows attackers with local access to potentially crash the kernel or execute arbitrary code. All Linux systems using MPTCP with affected kernel versions are vulnerable.

💻 Affected Systems

Products:

Linux kernel

Versions: Specific affected versions not specified in CVE, but patches exist for multiple stable branches.

Operating Systems: Linux distributions using vulnerable kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Requires MPTCP to be enabled and used. Not all Linux systems have MPTCP enabled by default.

📦 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 →

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 denial of service, or potential privilege escalation to kernel-level code execution.

🟠

Likely Case

Kernel crash causing system instability or denial of service.

🟢

If Mitigated

Limited to denial of service if exploit fails or system has additional protections.

🌐 Internet-Facing: LOW - Requires local access to exploit.

🏢 Internal Only: MEDIUM - Local attackers or compromised users could exploit this.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires local access and race condition triggering. No public exploit available at time of analysis.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Multiple stable kernel versions with fixes available (see references)

Vendor Advisory: https://git.kernel.org/stable/c/0e7814b028cd50b3ff79659d23dfa9da6a1e75e1

Restart Required: Yes

Instructions:

1. Identify your kernel version with 'uname -r'. 2. Update to a patched kernel version from your distribution's repositories. 3. Reboot the system to load the new kernel.

🔧 Temporary Workarounds

Disable MPTCP

linux

Disable the MPTCP subsystem if not required

echo 0 > /proc/sys/net/mptcp/enabled
sysctl -w net.mptcp.enabled=0

🧯 If You Can't Patch

Disable MPTCP subsystem if not required for operations
Implement strict access controls to limit local user privileges

🔍 How to Verify

Check if Vulnerable:

Check kernel version and MPTCP status: 'uname -r' and 'cat /proc/sys/net/mptcp/enabled'

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version is updated to a patched version and MPTCP is either disabled or patched

📡 Detection & Monitoring

Log Indicators:

Kernel panic logs
OOPs messages in dmesg
System crashes

Network Indicators:

Unusual local process behavior attempting to trigger race conditions

SIEM Query:

Search for kernel panic events or suspicious local process activity related to network timers

📊 Metadata

CVE ID: CVE-2024-46858

CVSS v3 Score: 7.0 (HIGH)

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

CWE: CWE-416

Published: September 27, 2024

Last Updated: December 24, 2025

🔗 References

📤 Share & Export

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