CVE-2024-26944
📋 TL;DR
This is a use-after-free vulnerability in the Linux kernel's Btrfs filesystem zoned mode implementation. It allows an attacker with local access to potentially crash the system or execute arbitrary code with kernel privileges. Systems using Btrfs with zoned mode enabled 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
Kernel panic leading to denial of service, or potential privilege escalation to root via arbitrary code execution in kernel context.
Likely Case
System crash or kernel panic during device replace operations, causing temporary denial of service.
If Mitigated
No impact if zoned mode is disabled or device replace operations are not performed.
🎯 Exploit Status
Requires local access and ability to trigger device replace operations on Btrfs zoned filesystems.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in kernel commits 1ec17ef59168a1a6f1105f5dc517f783839a5302 and 34ca809e055eca5cfe63d9c7efbf80b7c21b4e57
Vendor Advisory: https://git.kernel.org/stable/c/1ec17ef59168a1a6f1105f5dc517f783839a5302
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix commits. 2. Check your distribution's security advisories for specific patched kernel versions. 3. Reboot system after kernel update.
🔧 Temporary Workarounds
Disable Btrfs zoned mode
linuxAvoid using Btrfs zoned mode feature if not required
# Do not create Btrfs filesystems with zoned mode enabled
# Check existing filesystems: btrfs filesystem show
Avoid device replace operations
linuxTemporarily avoid performing device replace operations on Btrfs filesystems
# Monitor for device replace operations in logs
# Consider alternative data migration methods
🧯 If You Can't Patch
- Disable Btrfs zoned mode on all filesystems
- Implement strict access controls to prevent unauthorized users from performing device operations
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if Btrfs zoned mode is in use: uname -r and examine /proc/mounts for btrfs filesystemsCheck Version:
uname -rVerify Fix Applied:
Verify kernel version includes the fix commits: grep -q '1ec17ef59168a1a6f1105f5dc517f783839a5302\|34ca809e055eca5cfe63d9c7efbf80b7c21b4e57' /proc/version_signature📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages mentioning 'KASAN: slab-use-after-free in do_zone_finish'
- Btrfs device replace operation logs followed by system crashes
- dmesg output showing use-after-free in btrfs module
Network Indicators:
- None - this is a local filesystem vulnerability
SIEM Query:
source="kernel" AND "KASAN: slab-use-after-free" AND "do_zone_finish"