CVE-2025-39858
📋 TL;DR
A NULL pointer dereference vulnerability exists in the mlx4 Ethernet driver in the Linux kernel. This occurs when the page_pool_create() function returns an error pointer, but the code incorrectly checks for NULL instead of using IS_ERR(). This could cause kernel crashes or instability on systems using Mellanox network hardware.
💻 Affected Systems
- Linux kernel with mlx4 Ethernet driver enabled
📦 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
Kernel panic leading to system crash and denial of service, potentially disrupting network connectivity and system availability.
Likely Case
System instability or crash when the mlx4 driver encounters specific error conditions during network interface initialization.
If Mitigated
Minor performance impact or driver initialization failure without system crash if error handling catches the issue.
🎯 Exploit Status
Requires ability to trigger specific error conditions in the mlx4 driver, likely needing local access or control over hardware initialization.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits 7b77d8841a98a9f45c8a615222c698df8dec581c and e580beaf43d563aaf457f1c7f934002355ebfe7b
Vendor Advisory: https://git.kernel.org/stable/c/7b77d8841a98a9f45c8a615222c698df8dec581c
Restart Required: Yes
Instructions:
1. Update to a kernel 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 mlx4 driver
LinuxPrevent loading of the vulnerable driver module
echo 'blacklist mlx4_en' >> /etc/modprobe.d/blacklist.conf
rmmod mlx4_en
🧯 If You Can't Patch
- Ensure proper hardware configuration to minimize driver error conditions
- Implement monitoring for kernel panics or system instability related to network interfaces
🔍 How to Verify
Check if Vulnerable:
Check if mlx4 driver is loaded: lsmod | grep mlx4_en. Check kernel version against patched versions.Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes fix commits: grep -r 'mlx4_en_create_rx_ring' /proc/kallsyms or check kernel source.📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- Oops messages in dmesg
- Network interface initialization failures
Network Indicators:
- Sudden loss of network connectivity on affected interfaces
SIEM Query:
source="kernel" AND ("panic" OR "Oops" OR "mlx4")