CVE-2023-53662
📋 TL;DR
This CVE describes a memory leak vulnerability in the Linux kernel's ext4 filesystem when filename casefolding fails. It affects systems using ext4 with fscrypt encryption, potentially leading to kernel memory exhaustion over time. All Linux systems with vulnerable kernel versions 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 →⚠️ Risk & Real-World Impact
Worst Case
Sustained exploitation could lead to kernel memory exhaustion, causing system instability, denial of service, or kernel panic.
Likely Case
Gradual memory consumption leading to performance degradation and potential system instability over time.
If Mitigated
Minimal impact with proper monitoring and memory limits in place.
🎯 Exploit Status
Requires local access and ability to trigger filename casefolding failures on encrypted ext4 filesystems.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing the referenced git commits
Vendor Advisory: https://git.kernel.org/stable/c/1fb3f1bbfdb511034b0360dbeb0f6a8424ed2a5c
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version. 2. Reboot system to load new kernel. 3. Verify kernel version with 'uname -r'.
🔧 Temporary Workarounds
Disable fscrypt on ext4
linuxDisable filesystem encryption to prevent triggering the vulnerability
# Not recommended as it removes encryption functionality
Monitor kernel memory usage
linuxImplement monitoring for abnormal kernel memory consumption
# Monitor with: watch -n 1 'cat /proc/meminfo | grep -E "Slab|KernelStack"'
🧯 If You Can't Patch
- Implement strict memory limits and monitoring for kernel memory usage
- Restrict local user access to systems with vulnerable kernels
🔍 How to Verify
Check if Vulnerable:
Check kernel version and compare with patched versions in git commitsCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is updated and monitor for memory leaks during filename operations📡 Detection & Monitoring
Log Indicators:
- Kernel oom-killer events
- System instability logs
- Memory pressure warnings
Network Indicators:
- None - local vulnerability only
SIEM Query:
Search for kernel panic events or memory exhaustion alerts