CVE-2022-50068
📋 TL;DR
This CVE describes a NULL pointer dereference vulnerability in the Linux kernel's TTM (Translation Table Maps) memory management subsystem. When a buffer object's resource pointer is NULL, the kernel attempts to access it, causing a general protection fault that can crash the system or cause denial of service. This affects Linux systems using DRM graphics drivers that rely on TTM.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic leading to system crash and denial of service, potentially causing data loss or service disruption.
Likely Case
System crash or kernel panic when specific graphics operations are performed, requiring system reboot.
If Mitigated
Minor performance impact from the added NULL check, with no security impact when patched.
🎯 Exploit Status
Requires ability to trigger specific graphics operations through DRM/TTM interfaces. Likely requires local access or compromised process.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in kernel commits: 76672cd326c146ded2c2712ff257b8908dcf23d8, 9bd970d4097287778a4449452e70b35d0bfaa3aa, cf4b7387c0a842d64bdd7c353e6d3298174a7740
Vendor Advisory: https://git.kernel.org/stable/c/76672cd326c146ded2c2712ff257b8908dcf23d8
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix. 2. Check your distribution's security advisories for specific patched versions. 3. Reboot system after kernel update.
🔧 Temporary Workarounds
Disable affected graphics drivers
linuxPrevent loading of DRM drivers that use TTM subsystem
modprobe -r <affected_drm_driver>
echo 'blacklist <affected_drm_driver>' >> /etc/modprobe.d/blacklist.conf
🧯 If You Can't Patch
- Restrict local user access to systems with vulnerable kernels
- Monitor system logs for kernel panic or general protection fault messages
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if TTM/DRM modules are loaded: 'lsmod | grep ttm' and 'uname -r'Check Version:
uname -rVerify Fix Applied:
Verify kernel version is updated to one containing the fix commits, and check system logs for absence of the specific crash signature📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- general protection fault errors
- null-ptr-deref in KASAN reports
- TTM/DRM related crash logs
Network Indicators:
- None - this is a local kernel vulnerability
SIEM Query:
source="kernel" AND ("general protection fault" OR "null-ptr-deref" OR "ttm_bo_validate")