An issue was discovered in MBed OS 6.16.0. Its hci parsing software dynamically determines the length of certain hci packets by reading a byte from its header. Certain events cause a callback, the logic for which allocates a buffer (the length of which is determined by looking up the event type in a table). The subsequent write operation, however, copies the amount of data specified in the packet header, which may lead to a buffer overflow. This bug is trivial to exploit for a denial of service but is not certain to suffice to bring the system down and can generally not be exploited further because the exploitable buffer is dynamically allocated.