An iOS hacker and cybersecurity researcher today publicly released what he claimed to be a “permanent unpatchable bootrom exploit” An epic jailbreak that works on all iOS devices ranging from iPhone 4s (A5 chip) to iPhone 8 and iPhone X (A11 chip) The jailbreak only works on iPhones running Apple’s A5 and A11 chipsets and does not work on the latest two chipsets, i.e., A12 and A13. The Checkm8 exploit leverages unatchable security weaknesses in Apple’s SecureROM code.
Source: https://thehackernews.com/2019/09/bootrom-jailbreak-ios-exploit.html