CVE-2024-39510 – This is a use-after-free vulnerability in the L... (How to Fix)

Q: What is the severity of CVE-2024-39510?

CVE-2024-39510 has a CVSS score of 7.8 (HIGH). This is a use-after-free vulnerability in the Linux kernel's cachefiles subsystem that allows local attackers to potentially escalate privileges or crash the system. It affects Linux systems using the cachefilesd daemon for on-demand caching. The vulnerability occurs when multiple daemon threads race during cache restoration operations.

📋 TL;DR

This is a use-after-free vulnerability in the Linux kernel's cachefiles subsystem that allows local attackers to potentially escalate privileges or crash the system. It affects Linux systems using the cachefilesd daemon for on-demand caching. The vulnerability occurs when multiple daemon threads race during cache restoration operations.

💻 Affected Systems

Products:

Linux kernel

Versions: Linux kernel versions with cachefiles on-demand support, specifically vulnerable versions around 6.8.0

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ✅ No

Notes: Only vulnerable when cachefilesd daemon is running with on-demand mode enabled. Many distributions don't enable 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 →

⚠️ 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/panic causing system instability or denial of service, potentially leading to data corruption in cache operations.

🟢

If Mitigated

Minimal impact if cachefilesd is disabled or not in use; systems without local user access are largely unaffected.

🌐 Internet-Facing: LOW - This is a local kernel vulnerability requiring access to the cachefiles daemon interface.

🏢 Internal Only: MEDIUM - Local users or compromised services could exploit this to escalate privileges or crash the system.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Requires local access and ability to interact with cachefiles daemon. Race condition exploitation adds complexity.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Patched in kernel commits: 3958679c4915, 93064676a282, cb55625f8eb9, da4a82741606

Vendor Advisory: https://git.kernel.org/stable/c/3958679c49152391209b32be3357193300a51abd

Restart Required: Yes

Instructions:

1. Update Linux kernel to patched version from your distribution. 2. Reboot system to load new kernel. 3. Verify kernel version with 'uname -r'. 4. Check that cachefilesd is not vulnerable by ensuring patched kernel is running.

🔧 Temporary Workarounds

Disable cachefilesd service

linux

Stop and disable the cachefiles daemon if not required

sudo systemctl stop cachefilesd
sudo systemctl disable cachefilesd

Disable on-demand mode

linux

Configure cachefilesd to not use on-demand mode if service must remain running

Edit /etc/cachefilesd.conf and ensure 'ondemand' mode is not enabled
Restart cachefilesd: sudo systemctl restart cachefilesd

🧯 If You Can't Patch

Disable cachefilesd service completely if not essential for operations
Restrict access to cachefiles daemon socket to prevent local users from triggering the race condition

🔍 How to Verify

Check if Vulnerable:

Check if cachefilesd is running: 'systemctl status cachefilesd' and check kernel version: 'uname -r'

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version is patched (after 6.8.0 with fixes) and cachefilesd service status

📡 Detection & Monitoring

Log Indicators:

Kernel panic logs mentioning cachefiles
KASAN reports for slab-use-after-free in cachefiles_ondemand_daemon_read
System crashes during cache operations

Network Indicators:

None - this is a local kernel vulnerability

SIEM Query:

Process monitoring for cachefilesd abnormal termination or kernel panic events

📊 Metadata

CVE ID: CVE-2024-39510

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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