CVE-2025-39785
📋 TL;DR
A use-after-free vulnerability in the Linux kernel's hibmc DRM driver allows local attackers to cause kernel crashes or potentially execute arbitrary code. This affects systems using HiSilicon graphics hardware with vulnerable kernel versions. Attackers need local access to exploit this vulnerability.
💻 Affected Systems
- Linux kernel with hibmc DRM 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 →⚠️ Risk & Real-World Impact
Worst Case
Local privilege escalation to kernel mode, allowing complete system compromise and arbitrary code execution at the highest privilege level.
Likely Case
Kernel panic or system crash leading to denial of service, requiring system reboot to restore functionality.
If Mitigated
System remains stable with no impact if patched or if the hibmc driver is not loaded/used.
🎯 Exploit Status
Exploitation requires local access and knowledge of kernel memory layout. The use-after-free could potentially be leveraged for privilege escalation with additional exploitation techniques.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits 06d261a085a11600f5b577bb56a65fb2c3e57d0a or 8bed4ec42a4e0dc8113172696ff076d1eb6d8bcb
Vendor Advisory: https://git.kernel.org/stable/c/06d261a085a11600f5b577bb56a65fb2c3e57d0a
Restart Required: Yes
Instructions:
1. Update to a patched kernel version from your distribution vendor. 2. Reboot the system to load the new kernel. 3. Verify the hibmc driver is no longer vulnerable.
🔧 Temporary Workarounds
Disable hibmc driver
linuxPrevent loading of the vulnerable hibmc DRM driver module
echo 'blacklist hibmc' > /etc/modprobe.d/blacklist-hibmc.conf
rmmod hibmc
🧯 If You Can't Patch
- Restrict local user access to systems with HiSilicon graphics hardware
- Implement strict privilege separation and limit user capabilities
🔍 How to Verify
Check if Vulnerable:
Check if hibmc module is loaded: lsmod | grep hibmc. If loaded and kernel version is unpatched, system is vulnerable.Check Version:
uname -rVerify Fix Applied:
Check kernel version includes fix commits or verify hibmc driver is not causing crashes after update.📡 Detection & Monitoring
Log Indicators:
- Kernel oops messages
- System crash/panic logs
- hibmc driver error messages in dmesg
Network Indicators:
- None - this is a local vulnerability
SIEM Query:
Search for kernel panic events or hibmc driver errors in system logs