CVE-2024-40913 – This CVE describes a use-after-free vulnerabili... (How to Fix)

Q: What is the severity of CVE-2024-40913?

CVE-2024-40913 has a CVSS score of 7.8 (HIGH). This CVE describes a use-after-free vulnerability in the Linux kernel's cachefiles subsystem. It allows local attackers to potentially escalate privileges or crash the system by exploiting improper reference counting during file descriptor installation. Only systems using the cachefiles feature are affected.

📋 TL;DR

This CVE describes a use-after-free vulnerability in the Linux kernel's cachefiles subsystem. It allows local attackers to potentially escalate privileges or crash the system by exploiting improper reference counting during file descriptor installation. Only systems using the cachefiles feature are affected.

💻 Affected Systems

Products:

Linux kernel

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

Operating Systems: Linux distributions using vulnerable kernel versions

Default Config Vulnerable: ✅ No

Notes: Only vulnerable when cachefiles feature is enabled and in use. Many distributions disable this 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 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Local privilege escalation to root, kernel panic leading to denial of service, or arbitrary code execution in kernel context.

🟠

Likely Case

Kernel crash causing system instability or denial of service on affected systems.

🟢

If Mitigated

Minimal impact if cachefiles is disabled or systems are properly patched.

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

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

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires local access and knowledge of cachefiles subsystem. No public exploits known at this time.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Patches available in stable kernel versions referenced in CVE links

Vendor Advisory: https://git.kernel.org/stable/c/4b4391e77a6bf24cba2ef1590e113d9b73b11039

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version from your distribution's repositories. 2. Reboot system to load new kernel. 3. Verify kernel version after reboot.

🔧 Temporary Workarounds

Disable cachefiles

linux

Disable the cachefiles kernel module to prevent exploitation

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

🧯 If You Can't Patch

Disable cachefiles module if not required for system functionality
Implement strict access controls to limit local user privileges

🔍 How to Verify

Check if Vulnerable:

Check if cachefiles module is loaded: lsmod | grep cachefiles. If loaded and kernel version is unpatched, system is vulnerable.

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version matches patched version from distribution and cachefiles module is either not loaded or updated.

📡 Detection & Monitoring

Log Indicators:

Kernel oops messages
System crashes related to cachefiles
Unexpected cachefiles module activity

Network Indicators:

None - local exploit only

SIEM Query:

source="kernel" AND ("cachefiles" OR "use-after-free")

📊 Metadata

CVE ID: CVE-2024-40913

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-416

Published: July 12, 2024

Last Updated: November 3, 2025

🔗 References

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🔗 Related Vulnerabilities

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