CVE-2022-50206
📋 TL;DR
This CVE describes a race condition vulnerability in the Linux kernel's ARM64 instruction emulation sysctl handlers. When multiple processes concurrently modify the 'insn_emulation' sysctl settings, it can cause a kernel NULL pointer dereference leading to a system crash (kernel panic). This affects Linux systems running on ARM64 architecture with kernel versions containing the vulnerable code.
💻 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 →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 complete system crash and denial of service, potentially causing data loss or service disruption.
Likely Case
System crash requiring reboot when multiple privileged users or processes concurrently modify instruction emulation settings.
If Mitigated
No impact if sysctl settings aren't being modified concurrently or if the system is patched.
🎯 Exploit Status
Exploitation requires local access and ability to write to sysctl interface concurrently. Not a remote code execution vulnerability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits: 04549063d570, 07022e07017e, 353b4673d01c, 6a2fd114678d, 9d5fec6ba2e4
Vendor Advisory: https://git.kernel.org/stable/c/04549063d5701976034d8c2bfda3d3a8cbf0409f
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix commits. 2. For distributions: Use package manager (apt/yum/dnf) to update kernel package. 3. Reboot system to load new kernel.
🔧 Temporary Workarounds
Restrict sysctl access
linuxLimit access to /proc/sys/abi/cp15_barrier and related instruction emulation sysctl files to prevent concurrent modifications.
chmod 600 /proc/sys/abi/cp15_barrier
set appropriate SELinux/AppArmor policies
🧯 If You Can't Patch
- Restrict access to sysctl interface for non-privileged users
- Monitor for concurrent sysctl modification attempts and alert on suspicious activity
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if running on ARM64 architecture: uname -r && uname -mCheck Version:
uname -rVerify Fix Applied:
Verify kernel version includes fix commits: grep -q '04549063d570\|07022e07017e\|353b4673d01c\|6a2fd114678d\|9d5fec6ba2e4' /proc/version📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs mentioning 'Unable to handle kernel NULL pointer dereference'
- OOPs messages with call trace including 'emulation_proc_handler' or 'update_insn_emulation_mode'
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND ("NULL pointer dereference" OR "Oops: 96000006" OR "emulation_proc_handler")🔗 References
- https://git.kernel.org/stable/c/04549063d5701976034d8c2bfda3d3a8cbf0409f
- https://git.kernel.org/stable/c/07022e07017ee5540f5559b0aeb916e8383c1e1a
- https://git.kernel.org/stable/c/353b4673d01c512303c45cf2346f630cda73b5c9
- https://git.kernel.org/stable/c/6a2fd114678d7fc1b5a0f8865ae98f1c17787455
- https://git.kernel.org/stable/c/9d5fec6ba2e4117d196a8259ab54615ffe562460
- https://git.kernel.org/stable/c/af483947d472eccb79e42059276c4deed76f99a6
- https://git.kernel.org/stable/c/b51881b1da57fe9877125dfdd0aac5172958fcfd
- https://git.kernel.org/stable/c/cc69ef95988b9ef2fc730ec452a7441efb90ef5e
