The checkra1n iPhone jailbreak is now available to hackers and iPhone users who may recklessly use it. The tool is based on the BootROM exploit called checkm8, released in September by a hacker that goes by the name axi0mX. The exploit leverages the fact the chips BootROM is read-only memory (ROM) that holds startup (or boot-up) instructions for iPhones. Because the vulnerability can t be patched via a security update, the exploit code can’t be fixed.
Source: https://threatpost.com/checkra1n-jailbreak-stirs-concerns/150182/