CVE-2025-38408
📋 TL;DR
A NULL pointer dereference vulnerability in the Linux kernel's genirq/irq_sim module occurs when simulation work context pointers are not properly initialized. This can cause kernel crashes or potential privilege escalation if exploited. Systems running vulnerable Linux kernel versions with the irq_sim module loaded are affected.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic leading to system crash, or potential local privilege escalation to kernel mode if combined with other vulnerabilities.
Likely Case
Kernel crash causing system instability or denial of service when the irq_sim module is used.
If Mitigated
Minimal impact if the irq_sim module is not loaded or the system is patched.
🎯 Exploit Status
Requires local access and ability to trigger the irq_sim functionality. No public exploits known at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patches available in stable kernel trees (commits: 186df821de0f, 19bd7597858d, 7f73d1def725, 8a2277a3c9e4, c71aa4bb528a)
Vendor Advisory: https://git.kernel.org/stable/c/186df821de0f34490ed5fc0861243748b2483861
Restart Required: Yes
Instructions:
1. Update to a patched kernel version from your distribution's repositories. 2. Rebuild kernel if using custom kernel. 3. Reboot system to load new kernel.
🔧 Temporary Workarounds
Unload irq_sim module
linuxPrevent loading of the vulnerable irq_sim module if not required
rmmod irq_sim
echo 'blacklist irq_sim' >> /etc/modprobe.d/blacklist.conf
🧯 If You Can't Patch
- Ensure irq_sim module is not loaded (check with lsmod)
- Restrict local user access to systems where kernel module loading is required
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if irq_sim module is loaded: uname -r && lsmod | grep irq_simCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is updated and irq_sim module shows proper initialization in kernel logs📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- NULL pointer dereference errors in kernel logs
- irq_sim module crash logs
Network Indicators:
- None - this is a local kernel vulnerability
SIEM Query:
source="kernel" AND ("NULL pointer dereference" OR "irq_sim" OR "kernel panic")🔗 References
- https://git.kernel.org/stable/c/186df821de0f34490ed5fc0861243748b2483861
- https://git.kernel.org/stable/c/19bd7597858dd15802c1d99fcc38e528f469080a
- https://git.kernel.org/stable/c/7f73d1def72532bac4d55ea8838f457a6bed955c
- https://git.kernel.org/stable/c/8a2277a3c9e4cc5398f80821afe7ecbe9bdf2819
- https://git.kernel.org/stable/c/c71aa4bb528ae6f8fd7577a0a39e5a03c60b04fb
- https://git.kernel.org/stable/c/ec3656a8cb428d763def32bc2fa695f94be23629
