CVE-2025-38376: 
Linux Kernel vulnerability analysis and mitigation

CVE-2025-38376 was discovered in the Linux kernel and disclosed on July 25, 2025. The vulnerability affects the USB chipidea UDC (USB Device Controller) component during system suspend/resume operations. This issue specifically impacts systems where USB gadget is enabled as Ethernet and data transfer occurs over USB Ethernet connections (NVD).

The vulnerability occurs when the USB device controller is suspended while the USB bus remains active. In this scenario, the USB host continues to transfer data with the device, and the device continues to queue USB requests after the controller is suspended and its clock is gated off. When the UDC driver attempts to access registers at this point, the system hangs (NVD).

When exploited, this vulnerability can cause system hangs during suspend operations, particularly when there is active data transfer over USB Ethernet connections. The issue is triggered specifically when a delayed TCP ACK packet occurs after the controller is suspended (NVD).

The correct mitigation involves disconnecting the device from the host when the USB bus is not in suspend state. This allows the host to receive the disconnect event and stop data transfer in time. The system is designed to automatically reconnect the device after system resume. For USB wakeup functionality, the connection is maintained only when the USB device controller has enabled wakeup capability (NVD).