CVE-2025-21783
📋 TL;DR
A NULL pointer dereference vulnerability in the Linux kernel's gpiolib subsystem can cause kernel crashes when gpiochip_get_ngpios() is called via bgpio_init() with error conditions. This affects Linux systems using GPIO functionality, potentially leading to denial of service. The vulnerability requires local access to trigger.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Complete system crash/kernel panic requiring reboot, potentially causing data loss or service disruption.
Likely Case
Local denial of service through kernel crash when specific GPIO operations fail during initialization.
If Mitigated
Minimal impact with proper access controls preventing unprivileged users from triggering the vulnerable code path.
🎯 Exploit Status
Requires ability to trigger specific error conditions during GPIO initialization, typically needing appropriate permissions.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits: 189fb76215e479c10731baabb50f1a352d2078f5, 4d9b2b62e1136d10f661ec4c0c268140b6f74f4f, 7b4aebeecbbd5b5fe73e35fad3f62ed21aa7ef44, a7052afa9eae2239e25943baa8817a6a56e8aa68
Vendor Advisory: https://git.kernel.org/stable/c/189fb76215e479c10731baabb50f1a352d2078f5
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 GPIO functionality
linuxPrevent use of GPIO subsystem if not required
modprobe -r gpiochip_module_name
echo 'blacklist gpiochip_module_name' >> /etc/modprobe.d/blacklist.conf
🧯 If You Can't Patch
- Restrict access to GPIO devices to trusted users only
- Monitor system logs for kernel panic/crash events related to GPIO operations
🔍 How to Verify
Check if Vulnerable:
Check kernel version and compare with patched versions from kernel git repository. Vulnerable if using kernel without the fix commits.Check Version:
uname -rVerify Fix Applied:
Verify kernel version contains one of the fix commit hashes: grep -q '189fb76215e479c10731baabb50f1a352d2078f5\|4d9b2b62e1136d10f661ec4c0c268140b6f74f4f\|7b4aebeecbbd5b5fe73e35fad3f62ed21aa7ef44\|a7052afa9eae2239e25943baa8817a6a56e8aa68' /proc/version📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- NULL pointer dereference errors in dmesg
- GPIO-related crash reports
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND ("NULL pointer dereference" OR "kernel panic" OR "GPIO")