https://www.theregister.co.uk/2019/08/20/apples_ios_update_jailbreak/

iPhone hackers have discovered Apple's most recent iOS update, 12.4, released in July, accidentally reopened a code-execution vulnerability that was previously patched – a vulnerability that can be abused to jail-break iThings.

Pwn20wnd, the developer of the iPhone jail-breaking tool unc0ver, says the newest version of their software, 3.5.2, successfully exploits the SockPuppet flaw on iOS 12.4 to unlock a fully patched up-to-date device from the walled garden of Apple's App Store, thus allowing any third-party software to be installed and run.