CVE-2022-49980
📋 TL;DR
A race condition in the Linux kernel's USB gadget subsystem allows a use-after-free vulnerability when processing uevent notifications. This can lead to kernel memory corruption and potential privilege escalation. Systems using USB gadget functionality with affected 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 →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic, system crash, or privilege escalation to root via kernel memory corruption leading to arbitrary code execution.
Likely Case
System instability, kernel panic, or denial of service due to memory corruption.
If Mitigated
No impact if patched or if USB gadget functionality is not used.
🎯 Exploit Status
Discovered by syzbot fuzzer. Exploitation requires local access and ability to trigger uevents while USB gadget drivers are being unbound.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in kernel commits f44b0b95d50fffeca036e1ba36770390e0b519dd and 2191c00855b03aa59c20e698be713d952d51fc18
Vendor Advisory: https://git.kernel.org/stable/c/2191c00855b03aa59c20e698be713d952d51fc18
Restart Required: Yes
Instructions:
1. Update to a kernel version containing the fix. 2. For distributions: Apply security updates from your vendor. 3. Rebuild kernel if compiling from source. 4. Reboot system to load patched kernel.
🔧 Temporary Workarounds
Disable USB gadget functionality
linuxRemove USB gadget support if not needed by disabling CONFIG_USB_GADGET in kernel configuration
Check if enabled: grep CONFIG_USB_GADGET /boot/config-$(uname -r)
To disable: Recompile kernel with CONFIG_USB_GADGET=n
🧯 If You Can't Patch
- Restrict access to uevent triggering mechanisms to trusted users only
- Monitor for kernel panic logs and investigate any system instability related to USB operations
🔍 How to Verify
Check if Vulnerable:
Check kernel version and if USB gadget is enabled: uname -r && grep CONFIG_USB_GADGET /boot/config-$(uname -r)Check Version:
uname -rVerify Fix Applied:
Verify kernel version is patched: Check if kernel includes the fix commits or is newer than vulnerable versions📡 Detection & Monitoring
Log Indicators:
- Kernel panic messages
- KASAN reports of use-after-free in usb_udc_uevent
- System crashes during USB operations
Network Indicators:
- None - local vulnerability only
SIEM Query:
source="kernel" AND ("KASAN" OR "use-after-free" OR "usb_udc_uevent" OR "kernel panic")