CVE-2026-10647

The USB CDC-NCM device class subsys/usb/devicenext/class/usbdcdcncm.c ignores the return value of usbdepenqueue in its ethernet transmit callback cdcncmsend. When the enqueue fails, the function still calls ksemtake&data-syncsem, KFOREVER, blocking on a completion semaphore that is only ever...

CVE-2026-10647

The USB CDC-NCM device class subsys/usb/devicenext/class/usbdcdcncm.c ignores the return value of usbdepenqueue in its ethernet transmit callback cdcncmsend. When the enqueue fails, the function still calls ksemtake&data-;syncsem, KFOREVER, blocking on a completion semaphore that is only ever...

CVE-2026-10647 Deadlock denial of service in USB CDC-NCM device class on TX enqueue failure

The USB CDC-NCM device class subsys/usb/devicenext/class/usbdcdcncm.c ignores the return value of usbdepenqueue in its ethernet transmit callback cdcncmsend. When the enqueue fails, the function still calls ksemtake&data-syncsem, KFOREVER, blocking on a completion semaphore that is only ever...

CVE-2026-10647

The CVE concerns the USB CDC-NCM driver (subsys/usb/device_next/class/usbd_cdc_ncm.c) in Zephyr. The code ignores the return value of usbd_ep_enqueue() in cdc_ncm_send(); when enqueue fails, it still calls k_sem_take(&data-sync_sem, K_FOREVER), waiting on a completion that is only signaled from t...

PT-2026-53748

Name of the Vulnerable Software and Affected Versions Zephyr versions prior to 4.4.0 Description The USB CDC-NCM device class contains a flaw where the cdc ncm send function ignores the return value of usbd ep enqueue. If the enqueue operation fails—which occurs when the USB bus is suspended,...