CVE-2022-48938
📋 TL;DR
This CVE describes an integer overflow vulnerability in the Linux kernel's CDC-NCM network driver. A malicious or broken USB device could trigger this overflow during packet processing, potentially causing kernel crashes or denial of service. Systems using affected Linux kernel versions with CDC-NCM enabled are vulnerable.
💻 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
Kernel panic leading to system crash and denial of service, potentially requiring physical access to restart the system.
Likely Case
System instability, kernel crashes, or denial of service when connecting malicious USB network devices.
If Mitigated
Minor performance impact or connection issues with specific USB network devices.
🎯 Exploit Status
Exploitation requires physical USB device access or USB-over-IP capability. No public exploits known at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing the fix commits (e.g., 5.15.90+, 5.19.17+, 6.0.15+, 6.1.1+)
Vendor Advisory: https://git.kernel.org/stable/c/49909c9f8458cacb5b241106cba65aba5a6d8f4c
Restart Required: Yes
Instructions:
1. Update Linux kernel to patched version via distribution package manager. 2. For custom kernels, apply the fix commits from kernel.org. 3. Reboot system to load new kernel.
🔧 Temporary Workarounds
Disable CDC-NCM module
linuxPrevent loading of vulnerable kernel module
echo 'blacklist cdc_ncm' >> /etc/modprobe.d/blacklist-cdc-ncm.conf
rmmod cdc_ncm
Restrict USB device access
allLimit physical USB port access to trusted devices only
🧯 If You Can't Patch
- Implement strict physical security controls for USB ports
- Disable USB network device functionality where not required
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if cdc_ncm module is loaded: 'uname -r' and 'lsmod | grep cdc_ncm'Check Version:
uname -rVerify Fix Applied:
Verify kernel version is patched and test with USB network device functionality📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- System crash dumps
- CDC-NCM driver error messages in dmesg
Network Indicators:
- Sudden loss of USB network connectivity
- Unusual USB device connection patterns
SIEM Query:
source="kernel" AND ("panic" OR "Oops" OR "cdc_ncm")🔗 References
- https://git.kernel.org/stable/c/49909c9f8458cacb5b241106cba65aba5a6d8f4c
- https://git.kernel.org/stable/c/69560efa001397ebb8dc1c3e6a3ce00302bb9f7f
- https://git.kernel.org/stable/c/7b737e47b87589031f0d4657f6d7b0b770474925
- https://git.kernel.org/stable/c/8d2b1a1ec9f559d30b724877da4ce592edc41fdc
- https://git.kernel.org/stable/c/9957fbf34f52a4d8945d1bf39aae400ef9a11246
- https://git.kernel.org/stable/c/a612395c7631918e0e10ea48b9ce5ab4340f26a6
