CVE-2025-22084
📋 TL;DR
A race condition in the Linux kernel's w1 (1-Wire) subsystem can cause a NULL pointer dereference when initializing UART-based 1-Wire bus masters. This vulnerability affects Linux systems using 1-Wire hardware connected via UART/serial interfaces. Successful exploitation could lead to kernel panic and system crash.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic leading to system crash and denial of service, potentially requiring physical access to restart affected systems.
Likely Case
System crash or kernel panic when initializing or using 1-Wire UART devices, causing temporary denial of service.
If Mitigated
No impact if 1-Wire UART functionality is not used or if systems are patched.
🎯 Exploit Status
Exploitation requires triggering the race condition during 1-Wire UART device initialization, which typically requires local access or ability to load/use 1-Wire modules.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel with commits 0dd6770a72f138dabea9eae87f3da6ffa68f0d06, 4f750b84628080ff0d67bf1af67a4967b740acf2, 64ab50577c59bb7049bec6b5c42d1c38e4029f29, or cc6b0ec7cccbf66ef3621e9e93296b7bd1f52298
Vendor Advisory: https://git.kernel.org/stable/c/0dd6770a72f138dabea9eae87f3da6ffa68f0d06
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix commits. 2. Reboot system to load new kernel. 3. Verify kernel version after reboot.
🔧 Temporary Workarounds
Disable 1-Wire UART module
linuxPrevent loading of the vulnerable w1_uart module
echo 'blacklist w1_uart' >> /etc/modprobe.d/blacklist.conf
rmmod w1_uart
Disable 1-Wire subsystem
linuxDisable entire 1-Wire subsystem if not needed
echo 'blacklist wire' >> /etc/modprobe.d/blacklist.conf
rmmod wire
🧯 If You Can't Patch
- Disable 1-Wire UART functionality in kernel configuration
- Restrict physical access to 1-Wire hardware interfaces
🔍 How to Verify
Check if Vulnerable:
Check if w1_uart module is loaded: lsmod | grep w1_uart. If loaded and kernel version is vulnerable, system is at risk.Check Version:
uname -rVerify Fix Applied:
Check kernel version includes fix commits: uname -r and verify against patched versions. Confirm w1_uart module loads without crashes.📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/kern.log or dmesg
- NULL pointer dereference errors mentioning w1_uart or serdev
Network Indicators:
- No network indicators - this is a local kernel vulnerability
SIEM Query:
Search for kernel panic events or NULL pointer dereference errors in system logs