CVE-2022-50076
📋 TL;DR
This CVE describes a memory leak vulnerability in the Linux kernel's CIFS (Common Internet File System) implementation. When deferred close operations are canceled, the kernel fails to properly clean up allocated memory structures, leading to gradual memory exhaustion over time. This affects any Linux system using CIFS/SMB file sharing.
💻 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
Sustained exploitation could lead to kernel memory exhaustion, causing system instability, crashes, or denial of service on affected systems.
Likely Case
Gradual memory leak over time during normal CIFS operations, potentially leading to performance degradation or system instability requiring reboots.
If Mitigated
With proper monitoring and regular patching, impact is minimal as memory leaks are slow and require specific CIFS usage patterns.
🎯 Exploit Status
Exploitation requires ability to trigger CIFS deferred close operations, typically through normal file operations. No known weaponized exploits.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits 60b6d38add7b9c17d6e5d49ee8e930ea1a5650c5, 860efae127888ae535bc4eda1b7f27642727c69e, or ca08d0eac020d48a3141dbec0a3cf64fbdb17cde
Vendor Advisory: https://git.kernel.org/stable/c/60b6d38add7b9c17d6e5d49ee8e930ea1a5650c5
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 CIFS/SMB
linuxIf CIFS/SMB file sharing is not required, disable it to prevent vulnerability triggering.
modprobe -r cifs
echo 'blacklist cifs' > /etc/modprobe.d/blacklist-cifs.conf
🧯 If You Can't Patch
- Implement memory monitoring and alerting for systems using CIFS
- Restrict CIFS usage to essential operations only and monitor for abnormal memory consumption
🔍 How to Verify
Check if Vulnerable:
Check kernel version and verify if CIFS module is loaded: 'lsmod | grep cifs' and 'uname -r'Check Version:
uname -rVerify Fix Applied:
Verify kernel version contains the fix commits: 'uname -r' and check distribution patch notes📡 Detection & Monitoring
Log Indicators:
- Kernel oom-killer events
- System memory exhaustion warnings
- CIFS-related kernel panics
Network Indicators:
- Increased CIFS/SMB traffic followed by memory issues
SIEM Query:
source="kernel" AND ("out of memory" OR "oom" OR "panic") AND "cifs"