CVE-2022-50391
📋 TL;DR
This Linux kernel vulnerability allows local users to leak kernel memory through the set_mempolicy_home_node system call. When the system encounters certain virtual memory areas with specific memory policies, it fails to properly free allocated memory, creating a memory leak. This affects all Linux systems with vulnerable kernel versions.
💻 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 →⚠️ Risk & Real-World Impact
Worst Case
An attacker could repeatedly trigger the memory leak to exhaust kernel memory, potentially causing system instability, denial of service, or facilitating other attacks through memory exhaustion.
Likely Case
Local users can cause gradual kernel memory depletion, leading to performance degradation and potential system crashes over time.
If Mitigated
With proper access controls limiting local user privileges, the impact is reduced to authorized users only, but the kernel memory leak risk remains for those with access.
🎯 Exploit Status
Exploitation requires local access and knowledge of memory management internals. The attacker needs to create specific memory mapping conditions to trigger the leak.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits 0ce4cc6d269ddc448a825955b495f662f5d9e153, 38ce7c9bdfc228c14d7621ba36d3eebedd9d4f76, or 4ca0eb6b2f3add8c5daefb726ce57dc95d103d33
Vendor Advisory: https://git.kernel.org/stable/c/0ce4cc6d269ddc448a825955b495f662f5d9e153
Restart Required: Yes
Instructions:
1. Update to a patched kernel version from your distribution vendor. 2. Reboot the system to load the new kernel. 3. Verify the kernel version after reboot.
🔧 Temporary Workarounds
Restrict system call access
allUse seccomp or other security mechanisms to block the set_mempolicy_home_node system call for untrusted users
# Use seccomp profiles or AppArmor/SELinux policies to restrict system call access
🧯 If You Can't Patch
- Implement strict access controls to limit local user privileges
- Monitor system memory usage for unusual patterns indicating potential exploitation
🔍 How to Verify
Check if Vulnerable:
Check kernel version and compare with distribution security advisories. Vulnerable if using kernel versions before the fix commits.Check Version:
uname -rVerify Fix Applied:
Verify kernel version contains one of the fix commits: 0ce4cc6d269ddc448a825955b495f662f5d9e153, 38ce7c9bdfc228c14d7621ba36d3eebedd9d4f76, or 4ca0eb6b2f3add8c5daefb726ce57dc95d103d33📡 Detection & Monitoring
Log Indicators:
- Unusual memory allocation patterns in kernel logs
- System performance degradation logs
Network Indicators:
- None - this is a local vulnerability
SIEM Query:
Search for repeated set_mempolicy_home_node system calls from non-privileged users