CVE-2022-50300
📋 TL;DR
A use-after-free vulnerability in the Linux kernel's Btrfs filesystem driver allows local attackers to potentially crash the system or execute arbitrary code. This affects Linux systems using Btrfs filesystem when accessing degraded storage arrays without proper mount options. Attackers need local access to exploit this vulnerability.
💻 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
Local privilege escalation to kernel-level code execution, leading to complete system compromise.
Likely Case
Kernel panic or system crash causing denial of service.
If Mitigated
No impact if system doesn't use Btrfs or has proper degraded mount options configured.
🎯 Exploit Status
Requires local access and specific Btrfs configuration conditions to trigger.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions with commits: 169a4cf46882974d4db6d85eb623ec898e51bbc0, 1742e1c90c3da344f3bb9b1f1309b3f47482756a, b8e7ed42bc3ca0d0e4191ee394d34962d3624c22, fce3713197ebba239e1c7e02174ed216ea1ee014
Vendor Advisory: https://bugzilla.kernel.org/show_bug.cgi?id=216721
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version. 2. Reboot system. 3. Verify kernel version matches patched release.
🔧 Temporary Workarounds
Avoid degraded Btrfs mounts
linuxEnsure Btrfs filesystems are mounted with 'degraded' option when devices are missing
mount -o degraded /dev/sdX /mountpoint
Use alternative filesystem
linuxTemporarily use ext4 or other filesystems instead of Btrfs
🧯 If You Can't Patch
- Restrict local user access to systems using Btrfs
- Ensure all Btrfs mounts use 'degraded' option when devices are missing
🔍 How to Verify
Check if Vulnerable:
Check kernel version and verify if Btrfs is in use with 'cat /proc/filesystems | grep btrfs' and 'mount | grep btrfs'Check Version:
uname -rVerify Fix Applied:
Check kernel version matches patched release and verify Btrfs functionality📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- Btrfs error logs in dmesg
- System crash reports
Network Indicators:
- None - local exploit only
SIEM Query:
Search for kernel panic events or Btrfs error messages in system logs