CVE-2022-50255
📋 TL;DR
A memory safety vulnerability in the Linux kernel's tracing subsystem allows unprivileged local users to crash the kernel or potentially execute arbitrary code. The vulnerability occurs when synthetic events read string values without proper memory access validation, enabling user-space addresses to be passed to kernel functions. This affects all Linux systems with kernel tracing 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 →⚠️ Risk & Real-World Impact
Worst Case
Local privilege escalation to kernel-level code execution, allowing complete system compromise.
Likely Case
Kernel panic leading to denial of service (system crash) when malicious user-space addresses are accessed.
If Mitigated
Limited impact if kernel tracing is disabled or access controls restrict /sys/kernel/tracing.
🎯 Exploit Status
The CVE description includes a working exploit sequence. Exploitation requires local access and ability to write to tracing files.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits: 0934ae9977c2, 149198d0b884, d9c79fbcbdb6, or f8bae1853196
Vendor Advisory: https://git.kernel.org/stable/c/0934ae9977c27133449b6dd8c6213970e7eece38
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution. 2. Reboot system to load new kernel. 3. Verify kernel version matches patched release.
🔧 Temporary Workarounds
Disable kernel tracing
linuxPrevents access to vulnerable tracing functionality
echo 0 > /sys/kernel/tracing/tracing_on
chmod 000 /sys/kernel/tracing
Restrict tracing access
linuxLimit which users can access tracing subsystem
chmod 700 /sys/kernel/tracing
setfacl -m u:root:rwx /sys/kernel/tracing
🧯 If You Can't Patch
- Disable kernel tracing subsystem completely
- Implement strict access controls on /sys/kernel/tracing directory
🔍 How to Verify
Check if Vulnerable:
Check if /sys/kernel/tracing exists and is writable, and kernel version is unpatchedCheck Version:
uname -rVerify Fix Applied:
Check kernel version includes fix commits or test the exploit sequence no longer causes crash📡 Detection & Monitoring
Log Indicators:
- Kernel panic logs
- Oops messages in dmesg
- Failed string operations in tracing subsystem
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND ("Oops" OR "panic" OR "tracing" AND "crash")