CVE-2024-47691
📋 TL;DR
This is a use-after-free vulnerability in the Linux kernel's F2FS filesystem driver, specifically in the garbage collection thread shutdown function. It allows local attackers with filesystem access to potentially crash the kernel or execute arbitrary code. Systems using F2FS filesystems are affected.
💻 Affected Systems
- Linux kernel with F2FS filesystem support
📦 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
Kernel panic leading to system crash or potential privilege escalation to kernel-level code execution.
Likely Case
Kernel crash causing system instability and denial of service.
If Mitigated
No impact if proper kernel patches are applied or F2FS is not used.
🎯 Exploit Status
Requires local access and ability to trigger F2FS shutdown operations. Race condition exploitation adds complexity.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Linux kernel with commits 7c339dee7eb0f8e4cadc317c595f898ef04dae30 or later
Vendor Advisory: https://git.kernel.org/stable/c/7c339dee7eb0f8e4cadc317c595f898ef04dae30
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix. 2. Check distribution-specific security advisories. 3. Reboot system after kernel update.
🔧 Temporary Workarounds
Disable F2FS usage
linuxAvoid using F2FS filesystems until patched
# Check mounted F2FS filesystems: mount | grep f2fs
# Unmount F2FS partitions if possible: umount /dev/sdX
🧯 If You Can't Patch
- Restrict local user access to systems with F2FS filesystems
- Monitor for kernel panic/crash events and investigate F2FS-related incidents
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if F2FS is in use: uname -r && mount | grep f2fsCheck Version:
uname -rVerify Fix Applied:
Verify kernel version includes fix commits and test F2FS operations📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- F2FS-related crash reports in dmesg
- Use-after-free warnings in kernel logs
Network Indicators:
- None - local vulnerability only
SIEM Query:
Search for: 'kernel panic' OR 'use-after-free' OR 'f2fs' in system logs