The Continuous Glucose Monitoring Service's Record Access Control Point (RACP) write handler `memcpy`s the entire attacker-supplied ATT write value into a fixed 20-byte BSS buffer.

A buffer overflow in the Bluetooth Continuous Glucose
Monitoring Service (CGMS) Record Access Control Point (RACP) write handler
allows an authenticated BLE peer to overflow a 20-byte static buffer into
adjacent BSS memory. The exploitable impact cannot be predetermined - it
is entirely dependent on the linker-assigned BSS layout of the specific
firmware build, which may vary.