CVE-2025-39707
📋 TL;DR
A NULL pointer dereference vulnerability in the AMD GPU driver for Linux kernels allows local attackers to cause a kernel panic (denial of service) by accessing a specific debugfs file. This affects systems with DCE hardware using the amdgpu driver. The vulnerability requires local access to the system.
💻 Affected Systems
- Linux kernel with AMD GPU driver (amdgpu)
📦 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 →⚠️ Risk & Real-World Impact
Worst Case
Local attacker causes kernel panic leading to system crash and denial of service, potentially requiring physical or remote console access to restore functionality.
Likely Case
Local user or process accidentally triggers kernel panic while accessing debugfs, causing temporary system downtime until reboot.
If Mitigated
With proper access controls on debugfs, only privileged users can trigger the vulnerability, limiting impact to administrative actions.
🎯 Exploit Status
Requires local access and knowledge of debugfs interface. Exploitation involves accessing /sys/kernel/debug/dri/*/amdgpu_dm_capabilities file.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel stable releases containing commits 83cfdc2b018cd9c0f927b781d4e07c0d4a911fac, 98e92fceb9507901e3e8b550e93b843306abd354, or b4a69f7f29c8a459ad6b4d8a8b72450f1d9fd288
Vendor Advisory: https://git.kernel.org/stable/c/83cfdc2b018cd9c0f927b781d4e07c0d4a911fac
Restart Required: No
Instructions:
1. Update Linux kernel to patched version from distribution repositories. 2. For custom kernels, apply the relevant commit from kernel git repository. 3. No reboot required for driver-only updates, but kernel updates typically require reboot.
🔧 Temporary Workarounds
Restrict debugfs access
allLimit access to debugfs filesystem to prevent unauthorized users from triggering the vulnerability
mount -o remount,noexec,nosuid,nodev -t debugfs debugfs /sys/kernel/debug
chmod 700 /sys/kernel/debug/dri/*
Disable debugfs
allCompletely disable debugfs if not required for system operation
umount /sys/kernel/debug
echo "debugfs" >> /etc/modprobe.d/blacklist.conf
🧯 If You Can't Patch
- Implement strict access controls on /sys/kernel/debug directory to limit access to trusted administrators only
- Monitor system logs for access attempts to amdgpu_dm_capabilities debugfs file and investigate unauthorized attempts
🔍 How to Verify
Check if Vulnerable:
Check if /sys/kernel/debug/dri/*/amdgpu_dm_capabilities exists and system has DCE hardware with amdgpu driver loadedCheck Version:
uname -rVerify Fix Applied:
Verify kernel version includes the fix commits or test accessing the debugfs file no longer causes kernel panic📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/kern.log or dmesg output
- Access to /sys/kernel/debug/dri/*/amdgpu_dm_capabilities in audit logs
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND "panic" AND "amdgpu" OR source="audit" AND path="/sys/kernel/debug/dri/*/amdgpu_dm_capabilities"