A vulnerability in the Linux kernel's Bluetooth L2CAP implementation was fixed by adding a missing encryption key size check for L2CAP_LE_CONN_REQ messages. This check is required to comply with the L2CAP/LE/CFC/BV-15-C specification, which expects a specific error response (L2CAP_CR_LE_BAD_KEY_SIZE) when the key size is insufficient. The flaw could allow an attacker to bypass encryption key size validation during Bluetooth LE connection requests.