https://arstechnica.com/information-technology/2019/09/developer-of-checkm8-explains-why-idevice-jailbreak-exploit-is-a-game-changer/

Often, when new iOS jailbreaks become public, the event is bitter-sweet. The exploit allowing people to bypass restrictions Apple puts into the mobile operating system allows hobbyists and researchers to customize their devices and gain valuable insights be peeking under the covers. That benefit is countered by the threat that the same jailbreak will give hackers a new way to install malware or unlock iPhones that are lost, stolen, or confiscated by unscrupulous authorities.