CVE-2024-26689 – A use-after-free vulnerability in the Linux ker... (How to Fix)

Q: What is the severity of CVE-2024-26689?

CVE-2024-26689 has a CVSS score of 7.8 (HIGH). A use-after-free vulnerability in the Linux kernel's Ceph filesystem driver allows attackers to potentially crash the kernel or execute arbitrary code. This affects systems using the Ceph distributed filesystem with vulnerable kernel versions. Attackers need local access to exploit this vulnerability.

📋 TL;DR

A use-after-free vulnerability in the Linux kernel's Ceph filesystem driver allows attackers to potentially crash the kernel or execute arbitrary code. This affects systems using the Ceph distributed filesystem with vulnerable kernel versions. Attackers need local access to exploit this vulnerability.

💻 Affected Systems

Products:

Linux kernel with Ceph filesystem support

Versions: Linux kernel versions before the fix commits (specific versions vary by distribution)

Operating Systems: Linux distributions with vulnerable kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects systems using the Ceph filesystem. Systems not using Ceph are not vulnerable.

📦 What is this software?

Debian Linux by Debian

View all CVEs affecting Debian Linux →

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 system crash or potential privilege escalation to kernel-level code execution, allowing complete system compromise.

🟠

Likely Case

Kernel crash causing system instability or denial of service, requiring system reboot to recover.

🟢

If Mitigated

Limited to denial of service on affected Ceph client systems if proper access controls prevent unauthorized local access.

🌐 Internet-Facing: LOW - Requires local access to exploit, not directly exploitable over network.

🏢 Internal Only: MEDIUM - Internal users with local access to Ceph client systems could cause denial of service or potentially escalate privileges.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: MEDIUM

Exploitation requires local access and knowledge of Ceph filesystem operations to trigger the race condition.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Fixed in kernel commits: 70e329b440762390258a6fe8c0de93c9fdd56c77, 7958c1bf5b03c6f1f58e724dbdec93f8f60b96fc, 8180d0c27b93a6eb60da1b08ea079e3926328214, ae20db45e482303a20e56f2db667a9d9c54ac7e7, cda4672da1c26835dcbd7aec2bfed954eda9b5ef

Vendor Advisory: https://git.kernel.org/stable/c/70e329b440762390258a6fe8c0de93c9fdd56c77

Restart Required: Yes

Instructions:

1. Update Linux kernel to version containing the fix commits. 2. Check your distribution's security advisories for specific patched kernel versions. 3. Reboot system after kernel update.

🔧 Temporary Workarounds

Disable Ceph filesystem

linux

Remove or disable Ceph filesystem support if not required

# Check if Ceph module is loaded: lsmod | grep ceph
# Unload module: sudo rmmod ceph
# Blacklist module: echo 'blacklist ceph' | sudo tee /etc/modprobe.d/blacklist-ceph.conf

🧯 If You Can't Patch

Restrict local access to Ceph client systems to trusted users only
Implement strict access controls and monitor for unusual Ceph filesystem operations

🔍 How to Verify

Check if Vulnerable:

Check kernel version and if Ceph module is loaded: uname -r && lsmod | grep ceph

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version is patched by checking if it includes the fix commits or is newer than vulnerable versions

📡 Detection & Monitoring

Log Indicators:

Kernel panic logs
Ceph client crash logs
System instability reports

Network Indicators:

Unusual Ceph client disconnections

SIEM Query:

source="kernel" AND ("panic" OR "oops") AND "ceph"

📊 Metadata

CVE ID: CVE-2024-26689

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: April 3, 2024

Last Updated: January 14, 2025

🔗 References

📤 Share & Export

📄 Export Markdown 📋 Export JSON

🔗 Related Vulnerabilities

If you're affected by CVE-2024-26689, you might also want to check these: