CVE-2023-53511
📋 TL;DR
This CVE describes a file descriptor leak in the Linux kernel's io_uring subsystem when performing buffered reads on filesystems that don't support non-blocking operations. The leak occurs during link-copy operations on filesystems like ocfs2, causing resource exhaustion and preventing proper unmounting. Systems running affected Linux kernel versions with io_uring enabled are vulnerable.
💻 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 →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
File descriptor exhaustion leading to denial of service, inability to unmount filesystems, and potential system instability requiring reboot.
Likely Case
Resource leaks during specific file operations on unsupported filesystems, causing performance degradation and filesystem management issues.
If Mitigated
Minimal impact with proper monitoring and resource limits in place.
🎯 Exploit Status
Exploitation requires local access and specific file operations on vulnerable filesystems.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in stable kernel versions via commits 10fb2e16ee6f, 54aa7f2330b8, 75a499fc9d66
Vendor Advisory: https://git.kernel.org/stable/c/10fb2e16ee6ffaf1716b9e90d007e6b300bfa457
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version. 2. Check distribution-specific security advisories. 3. Reboot system after kernel update.
🔧 Temporary Workarounds
Disable io_uring
linuxRemove io_uring support from kernel configuration
echo 'blacklist io_uring' > /etc/modprobe.d/io_uring.conf
update-initramfs -u
reboot
Avoid vulnerable filesystems
linuxDon't use ocfs2 or other filesystems that don't support nowait buffered reads
🧯 If You Can't Patch
- Monitor file descriptor usage with 'lsof' and 'cat /proc/sys/fs/file-nr'
- Implement resource limits for user processes to prevent exhaustion
🔍 How to Verify
Check if Vulnerable:
Check kernel version: uname -r and compare with affected range v5.18-v6.6Check Version:
uname -rVerify Fix Applied:
Verify kernel version is beyond affected range and check for backported patches in distribution kernel📡 Detection & Monitoring
Log Indicators:
- Kernel messages about file descriptor exhaustion
- Failed unmount operations with 'target is busy' errors
SIEM Query:
source="kernel" AND ("file descriptor" OR "EOPNOTSUPP" OR "target is busy")