The Bluetooth stack is the software layer in an operating system or device firmware that handles Bluetooth discovery, pairing, authentication, and data exchange. It sits between apps and the radio hardware, translating high-level requests into protocol messages and managing connections to headsets, phones, keyboards, cars, and other nearby devices.
In cyber security, the Bluetooth stack matters because it processes traffic from short range but untrusted sources. Bugs in pairing logic, protocol parsing, or state handling can lead to crashes, denial of service, or, in some cases, code execution if malformed packets are accepted. Defenders watch this layer closely because stability issues can reveal deeper memory-safety or interoperability problems. Common protections include applying vendor patches, limiting discoverability, turning off Bluetooth when unused, and using secure pairing methods for trusted devices.