CVE-2024-57839
📋 TL;DR
A Linux kernel readahead vulnerability causes occasional system hangs when used with NFS (Network File System). The issue occurs when the readahead window calculation becomes negative, leading to kernel instability. This affects Linux systems using NFS for file access.
💻 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
System becomes completely unresponsive (kernel hang), requiring hard reboot and potentially causing data loss or service disruption.
Likely Case
Intermittent system hangs during NFS read operations, leading to temporary service unavailability and degraded performance.
If Mitigated
Reduced readahead throughput but system remains operational without hangs.
🎯 Exploit Status
This is a reliability bug causing hangs, not a security vulnerability with traditional exploitation. Requires NFS usage and specific read patterns.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernels with revert commit 85351e4941a253e4c50fb7048bfc19b60b4ec44b or a220d6b95b1ae12c7626283d7609f0a1438e6437
Vendor Advisory: https://git.kernel.org/stable/c/85351e4941a253e4c50fb7048bfc19b60b4ec44b
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing revert commit. 2. Check distribution-specific security advisories. 3. Reboot system after kernel update.
🔧 Temporary Workarounds
Disable NFS readahead
linuxDisable readahead for NFS mounts to prevent the problematic code path
mount -o remount,noac,noreadahead /nfs/mount/point
Avoid NFS usage
allUse alternative file sharing protocols until kernel is patched
🧯 If You Can't Patch
- Monitor systems for unexplained hangs and have reboot procedures ready
- Consider migrating critical NFS workloads to unaffected systems or alternative storage
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if commit 7c877586da3178974a8a94577b6045a48377ff25 is present: git log --oneline | grep '7c877586da3'Check Version:
uname -rVerify Fix Applied:
Verify revert commit is present: git log --oneline | grep -E '85351e4941a|a220d6b95b1a'📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- System hang events in system logs
- NFS timeout errors
Network Indicators:
- NFS connection timeouts
- Increased NFS retransmissions
SIEM Query:
source="kernel" AND ("panic" OR "hang" OR "NFS timeout")