CVE-2024-40956
📋 TL;DR
This CVE describes a use-after-free vulnerability in the Linux kernel's dmaengine idxd driver. It allows an attacker to potentially execute arbitrary code or cause a kernel crash by exploiting improper list handling during interrupt processing. Systems running affected Linux kernel versions with idxd driver enabled are vulnerable.
💻 Affected Systems
- Linux kernel
📦 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 →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 privilege escalation leading to full system compromise, arbitrary code execution, or persistent denial of service.
Likely Case
Kernel panic or system crash causing denial of service, potentially leading to data corruption in specific scenarios.
If Mitigated
System remains stable with no impact if patched or idxd driver not in use.
🎯 Exploit Status
Exploitation requires local access and specific conditions with idxd driver active. Race condition makes reliable exploitation challenging.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits: 1b08bf5a17c66ab7dbb628df5344da53c8e7ab33, 83163667d881100a485b6c2daa30301b7f68d9b5, a14968921486793f2a956086895c3793761309dd, e3215deca4520773cd2b155bed164c12365149a7, faa35db78b058a2ab6e074ee283f69fa398c36a8
Vendor Advisory: https://git.kernel.org/stable/c/
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 idxd driver is using patched code.
🔧 Temporary Workarounds
Disable idxd driver
linuxPrevent loading of vulnerable idxd driver module
echo 'blacklist idxd' >> /etc/modprobe.d/blacklist.conf
rmmod idxd
🧯 If You Can't Patch
- Restrict local user access to systems with idxd hardware
- Implement strict privilege separation and monitor for suspicious kernel activity
🔍 How to Verify
Check if Vulnerable:
Check if idxd module is loaded: lsmod | grep idxd AND check kernel version against patched commitsCheck Version:
uname -rVerify Fix Applied:
Verify kernel version includes fix commits and idxd module loads without errors📡 Detection & Monitoring
Log Indicators:
- Kernel oops messages
- System crashes/panics related to dmaengine or idxd
- Unexpected process termination with kernel faults
Network Indicators:
- None - local exploitation only
SIEM Query:
source="kernel" AND ("idxd" OR "dmaengine" OR "use-after-free")🔗 References
- https://git.kernel.org/stable/c/1b08bf5a17c66ab7dbb628df5344da53c8e7ab33
- https://git.kernel.org/stable/c/83163667d881100a485b6c2daa30301b7f68d9b5
- https://git.kernel.org/stable/c/a14968921486793f2a956086895c3793761309dd
- https://git.kernel.org/stable/c/e3215deca4520773cd2b155bed164c12365149a7
- https://git.kernel.org/stable/c/faa35db78b058a2ab6e074ee283f69fa398c36a8
- https://git.kernel.org/stable/c/1b08bf5a17c66ab7dbb628df5344da53c8e7ab33
- https://git.kernel.org/stable/c/83163667d881100a485b6c2daa30301b7f68d9b5
- https://git.kernel.org/stable/c/a14968921486793f2a956086895c3793761309dd
- https://git.kernel.org/stable/c/e3215deca4520773cd2b155bed164c12365149a7
- https://git.kernel.org/stable/c/faa35db78b058a2ab6e074ee283f69fa398c36a8
- https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html
