CVE-2023-53173
📋 TL;DR
This CVE describes a memory leak vulnerability in the Linux kernel's pcn_uart driver when using debugfs_lookup() without proper cleanup. The vulnerability allows gradual memory exhaustion over time, potentially leading to system instability or denial of service. All Linux systems using the affected kernel versions with the pcn_uart driver loaded are affected.
💻 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
System memory exhaustion leading to kernel panic, system crash, or denial of service requiring physical reboot
Likely Case
Gradual memory consumption causing system slowdowns, application failures, or service degradation over time
If Mitigated
Minimal impact with proper monitoring and memory limits in place
🎯 Exploit Status
Requires ability to trigger debugfs operations on pcn_uart driver, typically needs local access
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions with commit 04a189c720aa2b6091442113ce9b9bc93552dff8 or later
Vendor Advisory: https://git.kernel.org/stable/c/04a189c720aa2b6091442113ce9b9bc93552dff8
Restart Required: Yes
Instructions:
1. Update to patched kernel version from your distribution vendor
2. Reboot system to load new kernel
3. Verify pcn_uart driver is not loaded if not needed
🔧 Temporary Workarounds
Disable pcn_uart driver
allPrevent loading of vulnerable driver module
echo 'blacklist pcn_uart' >> /etc/modprobe.d/blacklist.conf
rmmod pcn_uart
Disable debugfs
allRemove debugfs mount to prevent exploitation
umount /sys/kernel/debug
echo 'debugfs /sys/kernel/debug debugfs noauto 0 0' >> /etc/fstab
🧯 If You Can't Patch
- Monitor system memory usage and implement alerting for abnormal consumption
- Implement kernel module signing and loading restrictions to prevent unauthorized driver loading
🔍 How to Verify
Check if Vulnerable:
Check if pcn_uart module is loaded: lsmod | grep pcn_uartCheck Version:
uname -rVerify Fix Applied:
Check kernel version is patched: uname -r and verify against distribution security advisories📡 Detection & Monitoring
Log Indicators:
- Kernel oom-killer messages
- System memory exhaustion warnings in syslog
- Repeated pcn_uart driver loading/unloading
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND ("out of memory" OR "oom-killer" OR "pcn_uart")