CVE-2023-53235
📋 TL;DR
This CVE describes a use-after-free vulnerability in the Linux kernel's DRM (Direct Rendering Manager) test helpers. The vulnerability occurs during cleanup when KUnit-managed resources are freed in the wrong order, allowing a freed driver structure to be dereferenced. This affects systems running vulnerable Linux kernel versions with DRM testing enabled.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic, system crash, or potential local privilege escalation if an attacker can trigger the UAF to execute arbitrary code in kernel context.
Likely Case
System instability, kernel crashes, or denial of service when running DRM-related tests or during specific cleanup sequences.
If Mitigated
Minimal impact if DRM testing is not used; primarily affects development/testing environments rather than production systems.
🎯 Exploit Status
Exploitation requires triggering specific DRM test cleanup sequences, making it unlikely to be weaponized for widespread attacks.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits 139a27854bf5ce93ff9805f9f7683b88c13074dc and c9d8be0e533738b744abb669263c4750d4830009
Vendor Advisory: https://git.kernel.org/stable/c/139a27854bf5ce93ff9805f9f7683b88c13074dc
Restart Required: Yes
Instructions:
1. Update Linux kernel to a version containing the fix commits. 2. Reboot the system to load the new kernel. 3. Verify the fix by checking kernel version and ensuring DRM testing functions properly.
🔧 Temporary Workarounds
Disable DRM testing
linuxDisable KUnit DRM testing modules to prevent triggering the vulnerable code path.
modprobe -r drm_kunit_helper
echo 'blacklist drm_kunit_helper' >> /etc/modprobe.d/blacklist.conf
🧯 If You Can't Patch
- Ensure DRM testing modules are not loaded in production environments
- Restrict access to users who could trigger DRM test sequences
🔍 How to Verify
Check if Vulnerable:
Check if DRM testing modules are loaded and if kernel version is within affected range: 'lsmod | grep drm' and 'uname -r'Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes fix commits: 'uname -r' and check kernel changelog for commits 139a27854bf5ce93ff9805f9f7683b88c13074dc and c9d8be0e533738b744abb669263c4750d4830009📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- KASAN reports of use-after-free in drm_dev_put
- System crashes during DRM-related operations
Network Indicators:
- None - this is a local vulnerability
SIEM Query:
Search for kernel logs containing 'KASAN: slab-use-after-free' or 'drm_dev_put' error messages