CVE-2024-53216
📋 TL;DR
A use-after-free vulnerability in the Linux kernel's NFS server (nfsd) allows local attackers to potentially crash the system or execute arbitrary code. The issue occurs when reading cached export information triggers premature freeing of memory that's still being accessed. Systems running vulnerable Linux kernel versions with NFS server 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 →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
Limited impact if NFS server is disabled or access is restricted to trusted users.
🎯 Exploit Status
Requires local access to trigger the race condition via /proc/fs/nfsd/exports or similar interfaces. Exploitation requires precise timing.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patches available in stable kernel trees via git commits: 2e4854599200f4d021df8ae17e69221d7c149f3e, ad4363a24a5746b257c0beb5d8cc68f9b62c173f, bd8524148dd8c123334b066faa90590ba2ef8e6f, f8c989a0c89a75d30f899a7cabdc14d72522bb8d
Vendor Advisory: https://git.kernel.org/stable/c/2e4854599200f4d021df8ae17e69221d7c149f3e
Restart Required: Yes
Instructions:
1. Update to a patched kernel version from your distribution vendor. 2. Reboot the system to load the new kernel. 3. Verify the fix by checking kernel version.
🔧 Temporary Workarounds
Disable NFS server
linuxStop and disable the nfsd service if not required
systemctl stop nfs-server
systemctl disable nfs-server
Restrict access to /proc/fs/nfsd
linuxLimit which users can access the vulnerable proc interface
chmod 600 /proc/fs/nfsd/exports
setfacl -m u:root:rw /proc/fs/nfsd/exports
🧯 If You Can't Patch
- Disable NFS server functionality entirely
- Implement strict access controls to prevent unauthorized local users from accessing the system
🔍 How to Verify
Check if Vulnerable:
Check if nfsd is running and kernel version is unpatched: systemctl status nfs-server && uname -rCheck Version:
uname -rVerify Fix Applied:
Verify kernel version includes one of the fix commits and nfsd operates normally after patch📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- KASAN reports of use-after-free in svc_export_show
- RCU usage warnings in kernel logs
Network Indicators:
- Unusual local process accessing /proc/fs/nfsd files
SIEM Query:
source="kernel" AND ("KASAN: slab-use-after-free" OR "svc_export_show" OR "suspicious RCU usage")