A tethered exploit is an exploit that only works while the target device remains connected to an external tool, such as a computer, cable, or helper process. The outside connection may deliver payloads, keep the exploit alive, or complete a boot-time step that the device cannot finish on its own.
In cyber security, tethered exploits matter because they are often easier to control, test, and stop than fully untethered ones. They are common in lab research, jailbreak development, and firmware work, especially when attacking early boot code or recovery modes. For defenders, the dependency on an external link can be a limitation: disconnecting the tool, rebooting the device, or blocking the required interface may break the attack. Even so, tethered exploits can still be dangerous on physically accessible systems because they may bypass normal software protections while the connection is present.