CVE-2022-50221
📋 TL;DR
This CVE describes an out-of-bounds memory access vulnerability in the Linux kernel's Direct Rendering Manager (DRM) fbdev deferred I/O subsystem. Attackers could potentially read or write beyond allocated memory boundaries, leading to system crashes or information disclosure. This affects Linux systems with DRM graphics drivers and fbdev console support.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic leading to system crash, potential information disclosure from kernel memory, or local privilege escalation if combined with other vulnerabilities.
Likely Case
System instability, graphical corruption, or kernel crashes when using fbdev console with specific memory boundary conditions.
If Mitigated
Minimal impact with proper kernel hardening and memory protection mechanisms in place.
🎯 Exploit Status
Exploitation requires local access and specific conditions to trigger the out-of-bounds access. No public exploits known at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits 9c49ac792c63 or ae25885bdf59
Vendor Advisory: https://git.kernel.org/stable/c/9c49ac792c639dbec0728b513329a32461f72253
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution's repositories. 2. Reboot system to load new kernel. 3. Verify kernel version after reboot.
🔧 Temporary Workarounds
Disable fbdev console
linuxRemove framebuffer console support to avoid triggering the vulnerability
Remove 'vga=' or 'video=' parameters from kernel boot line
Set console=tty0 instead of console=tty1 in boot configuration
🧯 If You Can't Patch
- Restrict local user access to systems with graphical console requirements
- Implement kernel hardening features like KASLR and memory protection
🔍 How to Verify
Check if Vulnerable:
Check kernel version and compare with distribution's security advisory. Vulnerable if using kernel before fix commits.Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes the fix commits (9c49ac792c63 or ae25885bdf59) via 'git log' or distribution patch notes.📡 Detection & Monitoring
Log Indicators:
- Kernel oops messages
- System crash/panic logs
- Graphics subsystem errors in dmesg
Network Indicators:
- None - local vulnerability only
SIEM Query:
Search for kernel panic events or out-of-bounds memory access errors in system logs