The Bluetooth Low Energy (BLE) stack implementation on Cypress PSoC 4 through 3.62 devices does not properly restrict the BLE Link Layer header and executes certain memory contents upon receiving a packet with a Link Layer ID (LLID) equal to zero. This allows attackers within radio range to cause deadlocks, cause anomalous behavior in the BLE state machine, or trigger a buffer overflow via a crafted BLE Link Layer frame.