CVE-2022-49099
📋 TL;DR
This CVE addresses a DMA (Direct Memory Access) initialization vulnerability in the Linux kernel's Hyper-V vmbus driver. The issue occurs when device objects aren't properly initialized before registration, potentially leading to memory corruption or system instability. Systems using Hyper-V virtualization with affected Linux kernel versions 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic or system crash leading to denial of service, potentially allowing privilege escalation if combined with other vulnerabilities.
Likely Case
System instability, kernel warnings in logs, or device driver failures during Hyper-V device initialization.
If Mitigated
Minor performance impact or warning messages in system logs without functional disruption.
🎯 Exploit Status
Exploitation requires local access and specific conditions during device initialization.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in kernel commits 2fe4b8631427618175a32f125062df91a5fe3f73 and 3a5469582c241abca22500f36a9cb8e9331969cf
Vendor Advisory: https://git.kernel.org/stable/c/2fe4b8631427618175a32f125062df91a5fe3f73
Restart Required: Yes
Instructions:
1. Update Linux kernel to version containing the fix. 2. For distributions: Use package manager (apt/yum/dnf) to update kernel package. 3. Reboot system to load new kernel.
🔧 Temporary Workarounds
Disable Hyper-V integration services
linuxRemove or blacklist hv_vmbus driver to prevent vulnerability trigger
echo 'blacklist hv_vmbus' > /etc/modprobe.d/blacklist-hv_vmbus.conf
update-initramfs -u
reboot
🧯 If You Can't Patch
- Monitor system logs for DMA-related warnings and kernel panics
- Implement strict access controls to prevent unauthorized local access to affected systems
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if hv_vmbus module is loaded: uname -r && lsmod | grep hv_vmbusCheck Version:
uname -rVerify Fix Applied:
Verify kernel version is patched and check dmesg for absence of DMA initialization warnings📡 Detection & Monitoring
Log Indicators:
- WARNING messages about DMA-mapping.h at netvsc_probe
- Kernel tracebacks mentioning vmbus_device_register
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND "WARNING.*dma-mapping.h" AND "netvsc_probe"