CVE-2025-39685
📋 TL;DR
This CVE-2025-39685 is an out-of-bounds vulnerability in the Linux kernel's comedi pcl726 driver that allows local attackers to trigger a kernel crash or potentially execute arbitrary code by passing an invalid interrupt number. It affects systems using the comedi data acquisition framework with the pcl726 driver. The vulnerability requires local access to the system.
💻 Affected Systems
- Linux kernel with comedi pcl726 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 →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
Local privilege escalation leading to full system compromise via kernel code execution or denial of service through kernel panic.
Likely Case
Local denial of service through kernel crash or system instability when invalid IRQ numbers are passed to the driver.
If Mitigated
Minimal impact with proper access controls preventing unauthorized users from accessing comedi devices.
🎯 Exploit Status
Requires local access and ability to interact with comedi devices. Exploitation involves passing specially crafted IRQ numbers to trigger the vulnerability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel versions containing the fix commits: 0eb4ed2aa261dee228f1668dbfa6d87353e8162d, 5a33d07c94ba91306093e823112a7aa9727549f6, 96cb948408b3adb69df7e451ba7da9d21f814d00, a3cfcd0c78c80ca7cd80372dc28f77d01be57bf6, bab220b0bb5af652007e278e8e8357f952b0e1ea
Vendor Advisory: https://git.kernel.org/stable/c/0eb4ed2aa261dee228f1668dbfa6d87353e8162d
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 comedi module
linuxPrevent loading of the vulnerable comedi driver if not needed
echo 'blacklist comedi' >> /etc/modprobe.d/blacklist-comedi.conf
rmmod comedi
Restrict comedi device access
linuxLimit access to comedi devices to trusted users only
chmod 600 /dev/comedi*
chown root:root /dev/comedi*
🧯 If You Can't Patch
- Implement strict access controls to prevent unauthorized users from accessing comedi devices
- Monitor system logs for comedi-related errors or kernel panics indicating exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check if comedi module is loaded: lsmod | grep comedi. Check kernel version against patched versions.Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes fix commits. Check that invalid IRQ handling no longer causes crashes.📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- comedi driver error logs
- Out of bounds memory access errors in kernel logs
Network Indicators:
- None - this is a local vulnerability
SIEM Query:
source="kernel" AND ("comedi" OR "pcl726" OR "out of bounds" OR "kernel panic")🔗 References
- https://git.kernel.org/stable/c/0eb4ed2aa261dee228f1668dbfa6d87353e8162d
- https://git.kernel.org/stable/c/5a33d07c94ba91306093e823112a7aa9727549f6
- https://git.kernel.org/stable/c/96cb948408b3adb69df7e451ba7da9d21f814d00
- https://git.kernel.org/stable/c/a3cfcd0c78c80ca7cd80372dc28f77d01be57bf6
- https://git.kernel.org/stable/c/bab220b0bb5af652007e278e8e8357f952b0e1ea
- https://git.kernel.org/stable/c/d8992c9a01f81128f36acb7c5755530e21fcd059
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
