CVE-2022-49699
📋 TL;DR
A race condition vulnerability in the Linux kernel's filemap subsystem can cause a NULL pointer dereference when handling sibling entries during concurrent read operations. This affects Linux systems with specific kernel versions and can lead to kernel crashes or denial of service. The vulnerability requires local access to exploit.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic leading to system crash and denial of service, potentially causing data loss or service disruption.
Likely Case
Local denial of service through kernel crash, requiring system reboot to recover.
If Mitigated
Minimal impact with proper access controls limiting local user privileges.
🎯 Exploit Status
Exploitation requires precise timing to trigger the race condition and local access to the system.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patched in kernel commits a66f131d30e53000f08301776bf85c912ef47aad and cb995f4eeba9d268fd4b56c2423ad6c1d1ea1b82
Vendor Advisory: https://git.kernel.org/stable/c/a66f131d30e53000f08301776bf85c912ef47aad
Restart Required: Yes
Instructions:
1. Update to a patched kernel version from your distribution vendor. 2. Reboot the system to load the new kernel.
🔧 Temporary Workarounds
Restrict local user access
linuxLimit the number of users with local shell access to reduce attack surface
Implement resource limits
linuxUse ulimit to restrict file operations by users
ulimit -n 1024
ulimit -u 100
🧯 If You Can't Patch
- Implement strict access controls to limit local user privileges
- Monitor system logs for kernel panic events and have incident response procedures ready
🔍 How to Verify
Check if Vulnerable:
Check kernel version and compare with distribution security advisories. Vulnerable if running unpatched kernel with the specific filemap code.Check Version:
uname -rVerify Fix Applied:
Verify kernel version is updated to a version containing the patch commits. Check distribution security advisories for confirmation.📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages in /var/log/messages or dmesg
- NULL pointer dereference errors in kernel logs
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND ("NULL pointer dereference" OR "kernel panic" OR "Oops")