The Bluetooth Low Energy (BLE) controller implementation in Espressif ESP-IDF 4.0 through 4.2 (for ESP32 devices) returns the wrong number of completed BLE packets and triggers a reachable assertion on the host stack when receiving a packet with an MIC failure. An attacker within radio range can silently trigger the assertion (which disables the target's BLE stack) by sending a crafted sequence of BLE packets.