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.

References

• https://nvd.nist.gov/vuln/detail/CVE-2024-48986
• mbed-ce/mbed-os#385
• https://github.com/mbed-ce/mbed-os/blob/54e8693ef4ff7e025018094f290a1d5cf380941f/connectivity/FEATURE_BLE/libraries/cordio_stack/ble-host/sources/hci/dual_chip/hci_evt.c#L3018