CVE-2022-50307
📋 TL;DR
This CVE-2022-50307 is an out-of-bounds read vulnerability in the Linux kernel's s390/cio subsystem. When devices are removed from the cio_ignore list, the kernel incorrectly accesses memory when checking if devices are online, potentially causing kernel crashes or information disclosure. This affects Linux systems running on IBM s390/zSeries architecture with specific I/O subchannel drivers like vfio_ccw.
💻 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 →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, or potential information disclosure from kernel memory
Likely Case
System instability or crashes when managing I/O devices through cio_ignore operations
If Mitigated
No impact if the vulnerable code path is not triggered
🎯 Exploit Status
Requires local access and ability to write to /proc/cio_ignore. Exploitation depends on specific I/O configuration.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in kernel commits: 0e501fd0f38e, 106ab66cf546, 1b6074112742
Vendor Advisory: https://git.kernel.org/stable/c/0e501fd0f38e42304bfa0d46a812d93f80294a87
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix commits. 2. Check your distribution's security advisories for specific patched versions. 3. Reboot the system after kernel update.
🔧 Temporary Workarounds
Restrict access to cio_ignore
linuxLimit write access to /proc/cio_ignore to prevent triggering the vulnerability
chmod 644 /proc/cio_ignore
chown root:root /proc/cio_ignore
Avoid using cio_ignore operations
linuxDo not use 'echo free >/proc/cio_ignore' or similar operations that trigger device scanning
🧯 If You Can't Patch
- Implement strict access controls on /proc/cio_ignore
- Monitor for system crashes or kernel panics related to I/O operations
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if running on s390 architecture with non-default I/O driversCheck Version:
uname -rVerify Fix Applied:
Verify kernel version includes the fix commits or check with 'uname -r' against patched versions📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- Out-of-bounds access errors in kernel logs
- System crashes during I/O operations
SIEM Query:
source="kernel" AND ("panic" OR "out of bounds" OR "cio_ignore")