CVE-2023-53538
📋 TL;DR
A race condition in the Linux kernel's Btrfs filesystem tree modification logging can lead to a NULL pointer dereference and kernel panic when performing logical inode resolution operations. This affects systems using Btrfs filesystem with kernel versions containing the vulnerable code. The vulnerability requires local access to trigger.
💻 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 →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 leading to system crash and denial of service, potentially causing data corruption or loss if occurring during critical filesystem operations.
Likely Case
System crash/reboot when specific Btrfs operations are performed under race conditions, resulting in temporary denial of service.
If Mitigated
No impact if patched or if Btrfs is not used.
🎯 Exploit Status
Requires local access and specific race conditions during Btrfs operations. Not trivial to exploit reliably.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patched in kernel commits 11f14402fe3437852cb44945b3b9f1bdb4032956 and 5cead5422a0e3d13b0bcee986c0f5c4ebb94100b
Vendor Advisory: https://git.kernel.org/stable/c/11f14402fe3437852cb44945b3b9f1bdb4032956
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix. 2. Check your distribution's security advisories for backported patches. 3. Reboot system after kernel update.
🔧 Temporary Workarounds
Disable Btrfs filesystem
linuxUse alternative filesystem like ext4 or XFS instead of Btrfs
# Migrate data to different filesystem
# Format partitions with ext4 instead of Btrfs
Restrict Btrfs operations
linuxLimit user access to Btrfs-specific operations that could trigger the race condition
# Use filesystem quotas
# Restrict user permissions on Btrfs volumes
🧯 If You Can't Patch
- Monitor system logs for Btrfs-related kernel panics and crashes
- Implement strict access controls to limit who can perform Btrfs operations
🔍 How to Verify
Check if Vulnerable:
Check kernel version and verify if Btrfs is in use: 'uname -r' and 'cat /proc/filesystems | grep btrfs'Check Version:
uname -rVerify Fix Applied:
Verify kernel version is updated and check if patch is included: 'grep -r "push_node_left\|tree_mod_log" /usr/src/linux' or check distribution security advisories📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages mentioning Btrfs
- NULL pointer dereference in Btrfs code
- Critical Btrfs errors in system logs
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND ("BTRFS critical" OR "NULL pointer dereference" OR "kernel panic")