CVE-2023-53248
📋 TL;DR
A NULL pointer dereference vulnerability in the AMD GPU driver for Linux kernel could cause kernel crashes or denial of service when using CPU to update page tables. This affects Linux systems with AMD GPUs using the affected driver code. The vulnerability occurs when dma_fence_wait() is called on uninitialized fence pointers.
💻 Affected Systems
- Linux kernel with AMD GPU driver (drm/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
Kernel panic leading to system crash and denial of service, potentially causing data loss or system instability.
Likely Case
System crash or kernel panic requiring reboot, resulting in temporary denial of service.
If Mitigated
Minimal impact with proper access controls limiting who can trigger GPU operations.
🎯 Exploit Status
Requires local access and ability to trigger specific GPU operations. Not trivial to exploit but could be discovered through fuzzing.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel with commits 187916e6ed9d0c3b3abc27429f7a5f8c936bd1f0, 78b25110eb8c6990f7f5096bc0136c12a2b4cc99, or aa9e9ba5748c524eb0925a2ef6984b78793646d6
Vendor Advisory: https://git.kernel.org/stable/c/187916e6ed9d0c3b3abc27429f7a5f8c936bd1f0
Restart Required: No
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. Rebuild kernel if using custom kernel with affected code.
🔧 Temporary Workarounds
Disable AMD GPU driver
LinuxTemporarily disable or blacklist the amdgpu kernel module to prevent exploitation
echo 'blacklist amdgpu' >> /etc/modprobe.d/blacklist-amdgpu.conf
update-initramfs -u
reboot
🧯 If You Can't Patch
- Restrict local user access to systems with AMD GPUs
- Implement strict privilege separation to limit who can perform GPU operations
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if amdgpu module is loaded: lsmod | grep amdgpu && uname -rCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is updated and check git log for fix commits in kernel source📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/kern.log or dmesg
- GPU driver crash logs
- System crash/reboot events
Network Indicators:
- None - local vulnerability only
SIEM Query:
EventID=41 OR Source="kernel" AND Message="BUG: unable to handle kernel NULL pointer dereference"