CVE-2024-46696
📋 TL;DR
This CVE describes a use-after-free vulnerability in the Linux kernel's NFS server component (nfsd). An attacker could potentially exploit this to cause a kernel crash or execute arbitrary code with kernel privileges. This affects Linux systems running NFS server with delegations enabled.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic leading to system crash or potential privilege escalation to root via arbitrary code execution in kernel context.
Likely Case
Kernel crash causing denial of service and system instability.
If Mitigated
Limited impact if NFS server is not running or delegations are disabled.
🎯 Exploit Status
Exploitation requires specific timing and conditions to trigger the use-after-free after dropping delegation reference.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patches available in stable kernel trees (commits 1116e0e372eb16dd907ec571ce5d4af325c55c10 and e0b66698a5ae41078f7490e8b3527013f5fccd6c)
Vendor Advisory: https://git.kernel.org/stable/c/1116e0e372eb16dd907ec571ce5d4af325c55c10
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from distribution vendor. 2. Reboot system to load new kernel. 3. Verify kernel version after reboot.
🔧 Temporary Workarounds
Disable NFS server
linuxStop and disable the NFS server service if not required.
systemctl stop nfs-server
systemctl disable nfs-server
Disable NFS delegations
linuxConfigure NFS server to disable delegations feature.
echo 'options nfsd nfs4_disable_idmapping=1' >> /etc/modprobe.d/nfs.conf
systemctl restart nfs-server
🧯 If You Can't Patch
- Disable NFS server completely if not required
- Restrict NFS server access to trusted networks only using firewall rules
🔍 How to Verify
Check if Vulnerable:
Check if NFS server is running and kernel version is unpatched: systemctl status nfs-server && uname -rCheck Version:
uname -rVerify Fix Applied:
Verify kernel version after update matches patched version and NFS server is either disabled or running with delegations disabled.📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/messages or dmesg
- NFS server crash logs
- Unexpected system reboots
Network Indicators:
- Unusual NFS traffic patterns
- Multiple connection attempts to NFS port 2049
SIEM Query:
source="kernel" AND ("panic" OR "Oops" OR "general protection fault") AND process="nfsd"