CVE-2022-50378
📋 TL;DR
This is a use-after-free vulnerability in the Linux kernel's DRM subsystem for Amlogic Meson display drivers. When unloading the driver (e.g., during rmmod), improper cleanup order causes the kernel to access freed memory, potentially leading to system crashes or kernel memory corruption. Systems using affected Amlogic hardware with vulnerable kernel versions are affected.
💻 Affected Systems
- Linux kernel with Amlogic Meson 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
Kernel panic, system crash, or potential privilege escalation if an attacker can trigger the driver unload and manipulate freed memory structures.
Likely Case
System instability or crash when unloading the affected display driver module, requiring reboot.
If Mitigated
No impact if the vulnerable driver isn't loaded or if patched kernel is used.
🎯 Exploit Status
Exploitation requires CAP_SYS_MODULE or root privileges to trigger driver unload. The vulnerability is triggered during normal driver cleanup.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel with fixes from the referenced commits
Vendor Advisory: https://git.kernel.org/stable/c/31c519981eb141c7ec39bfd5be25d35f02edb868
Restart Required: Yes
Instructions:
1. Update to a patched Linux kernel version from your distribution. 2. For custom kernels, apply the fix commits to the drm/meson driver. 3. Reboot the system after kernel update.
🔧 Temporary Workarounds
Prevent driver unloading
linuxPrevent unloading of the meson_drm driver module to avoid triggering the vulnerability.
echo 'install meson_drm /bin/false' >> /etc/modprobe.d/blacklist-meson.conf
Restrict module loading
linuxRestrict kernel module loading to authorized users only.
sysctl -w kernel.modules_disabled=1
echo 'kernel.modules_disabled=1' >> /etc/sysctl.conf
🧯 If You Can't Patch
- Restrict module loading/unloading to root only using kernel.modules_disabled or capabilities
- Monitor for driver unload attempts and system crashes
🔍 How to Verify
Check if Vulnerable:
Check if meson_drm driver is loaded: lsmod | grep meson_drm. Check kernel version: uname -r and compare with patched versions.Check Version:
uname -rVerify Fix Applied:
Verify kernel version is updated beyond vulnerable versions. Test unloading driver (if safe): rmmod meson_drm (should not crash).📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- KASAN use-after-free warnings in dmesg
- Driver unload events in system logs
Network Indicators:
- None - local vulnerability
SIEM Query:
source="kernel" AND ("KASAN" OR "use-after-free" OR "meson_drm")