CVE-2022-50351
📋 TL;DR
This CVE describes a memory leak vulnerability in the Linux kernel's CIFS (Common Internet File System) implementation. When the CIFS client is already shutting down, the xid (transaction ID) isn't properly freed in the cifs_create() function, leading to resource exhaustion over time. This affects Linux systems 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 →⚠️ Risk & Real-World Impact
Worst Case
Sustained exploitation could lead to kernel memory exhaustion, causing system instability, denial of service, or potential kernel crashes.
Likely Case
Gradual memory leak that may cause performance degradation or service interruptions for CIFS operations over extended periods.
If Mitigated
Minimal impact with proper monitoring and resource limits in place.
🎯 Exploit Status
Requires specific timing conditions where CIFS is shutting down while file creation operations are attempted.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patches available in stable kernel trees (see references)
Vendor Advisory: https://git.kernel.org/stable/c/593d877c39aa9f3fe1a4b5b022492886d7d700ec
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version from your distribution's repositories. 2. Reboot system to load new kernel.
🔧 Temporary Workarounds
Disable CIFS module
linuxPrevent loading of CIFS kernel module if not required
echo 'install cifs /bin/false' >> /etc/modprobe.d/disable-cifs.conf
rmmod cifs
🧯 If You Can't Patch
- Monitor system memory usage and kernel logs for signs of memory exhaustion
- Restrict CIFS usage to trusted networks and monitor for abnormal CIFS connection patterns
🔍 How to Verify
Check if Vulnerable:
Check kernel version and verify if CIFS module is loaded: lsmod | grep cifs && uname -rCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is updated and check patch inclusion in kernel source📡 Detection & Monitoring
Log Indicators:
- Kernel OOM (Out of Memory) messages
- Increased memory usage in /proc/meminfo
- CIFS connection errors
Network Indicators:
- Abnormal CIFS/SMB connection patterns during shutdown sequences
SIEM Query:
source="kernel" AND ("out of memory" OR "cifs" AND "error")