CVE-2024-26907 – This CVE-2024-26907 is a use-after-free vulnera... (How to Fix)

Q: What is the severity of CVE-2024-26907?

CVE-2024-26907 has a CVSS score of 7.8 (HIGH). This CVE-2024-26907 is a use-after-free vulnerability in the Linux kernel's RDMA/mlx5 driver that occurs when accessing Ethernet segments. It allows local attackers to potentially execute arbitrary code or cause denial of service by exploiting improper memory handling in the mlx5_ib_post_send function. Systems using Mellanox InfiniBand hardware with affected kernel versions are vulnerable.

📋 TL;DR

This CVE-2024-26907 is a use-after-free vulnerability in the Linux kernel's RDMA/mlx5 driver that occurs when accessing Ethernet segments. It allows local attackers to potentially execute arbitrary code or cause denial of service by exploiting improper memory handling in the mlx5_ib_post_send function. Systems using Mellanox InfiniBand hardware with affected kernel versions are vulnerable.

💻 Affected Systems

Products:

Linux kernel with mlx5_ib RDMA driver

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

Operating Systems: Linux distributions using affected kernel versions

Default Config Vulnerable: ⚠️ Yes

Notes: Requires Mellanox InfiniBand hardware and RDMA functionality enabled. Systems without mlx5_ib driver or RDMA hardware are not affected.

📦 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 →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Local privilege escalation to kernel-level code execution, potentially leading to full system compromise.

🟠

Likely Case

Kernel panic or system crash causing denial of service.

🟢

If Mitigated

Limited impact if proper kernel hardening and memory protection mechanisms are enabled.

🌐 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 kernel memory layout. The fortify source warning indicates memory corruption detection is active.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Linux kernel with commits: 185fa07000e0a81d54cf8c05414cebff14469a5c, 4d5e86a56615cc387d21c629f9af8fb0e958d350, 60ba938a8bc8c90e724c75f98e932f9fb7ae1b9d, 9a624a5f95733bac4648ecadb320ca83aa9c08fd, cad82f1671e41094acd3b9a60cd27d67a3c64a21

Vendor Advisory: https://git.kernel.org/stable/c/185fa07000e0a81d54cf8c05414cebff14469a5c

Restart Required: Yes

Instructions:

1. Update Linux kernel to version containing the fix commits. 2. For distributions: Use package manager (apt/yum/dnf) to update kernel package. 3. Reboot system to load new kernel.

🔧 Temporary Workarounds

Disable RDMA functionality

linux

Prevent loading of mlx5_ib driver to mitigate vulnerability

echo 'blacklist mlx5_ib' > /etc/modprobe.d/disable-mlx5-ib.conf
update-initramfs -u
reboot

Disable InfiniBand hardware

all

Disable Mellanox InfiniBand hardware at BIOS/UEFI level

🧯 If You Can't Patch

Restrict local user access to systems with vulnerable configuration
Implement strict privilege separation and limit users who can access RDMA functionality

🔍 How to Verify

Check if Vulnerable:

Check kernel version and if mlx5_ib module is loaded: lsmod | grep mlx5_ib

Check Version:

uname -r

Verify Fix Applied:

Verify kernel version is updated and check dmesg for absence of fortify warnings related to mlx5_ib

📡 Detection & Monitoring

Log Indicators:

Kernel logs showing 'fortify source warning' or 'field-spanning write' in mlx5_ib context
System crashes or kernel panics related to RDMA operations

Network Indicators:

Unusual RDMA traffic patterns from local users

SIEM Query:

source="kernel" AND ("fortify source" OR "mlx5_ib" OR "field-spanning write")

📊 Metadata

CVE ID: CVE-2024-26907

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 17, 2024

Last Updated: November 21, 2024

🔗 References

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🔗 Related Vulnerabilities

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