CVE-2024-50009
📋 TL;DR
This CVE describes a NULL pointer dereference vulnerability in the AMD P-State CPU frequency scaling driver in the Linux kernel. If cpufreq_cpu_get() returns NULL and the code doesn't check for this, it could cause a kernel panic or system crash. This affects Linux systems using the amd-pstate driver for AMD processors.
💻 Affected Systems
- Linux kernel with amd-pstate driver
📦 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic leading to system crash and denial of service, potentially requiring physical reboot of affected systems.
Likely Case
System instability or crash when the vulnerable code path is triggered during CPU frequency scaling operations.
If Mitigated
Minor system instability that may be recoverable without full system crash.
🎯 Exploit Status
Exploitation requires triggering the specific code path where cpufreq_cpu_get() returns NULL, which may require specific system conditions or targeted operations.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits 5493f9714e4cdaf0ee7cec15899a231400cb1a9f, 5f250d44b8191d612355dd97b89b37bbc1b5d2cb, or cd9f7bf6cad8b2d3876105ce3c9fc63460a046f6
Vendor Advisory: https://git.kernel.org/stable/c/5493f9714e4cdaf0ee7cec15899a231400cb1a9f
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 amd-pstate driver
linuxSwitch to alternative CPU frequency scaling driver (acpi-cpufreq) to avoid vulnerable code path
echo 'GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT amd_pstate=disable"' | sudo tee -a /etc/default/grub
sudo update-grub
sudo reboot
🧯 If You Can't Patch
- Monitor system logs for kernel panic or crash events related to cpufreq operations
- Implement system monitoring to detect and alert on unexpected reboots or system instability
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if amd-pstate driver is active: uname -r && grep -i amd_pstate /proc/cmdlineCheck Version:
uname -rVerify Fix Applied:
Verify kernel version contains fix commits and check dmesg for amd-pstate driver loading without errors📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/kern.log or dmesg
- NULL pointer dereference errors mentioning cpufreq or amd-pstate
- System crash/reboot events
Network Indicators:
- None - this is a local kernel vulnerability
SIEM Query:
source="kernel" AND ("NULL pointer dereference" OR "kernel panic") AND ("cpufreq" OR "amd-pstate")