Google security researcher Ian Beer, who works for the Project Zero team, last week highlighted an iOS 11.1.2 exploit called "tfp0," which he believes could be the basis for a future iOS 11.1.2 jailbreak.
Today, Beer released the exploit to the public. He says it should work on all iOS devices running iOS 11.1.2 or below, though he only personally tested iPhone 7, iPhone 6s, and a sixth-generation iPod touch.
What Beer released is not a full iOS 11 jailbreak as some had hoped, but what he's shared could potentially be used to create a jailbreak in the future.
tfp0 should work for all devices, the PoC local kernel debugger only for those I have to test on (iPhone 7, 6s and iPod Touch 6G) but adding more support should be easy — Ian Beer (@i41nbeer) December 11, 2017
iOS 11.1.2 is no longer the current version of iOS as Apple released iOS 11.2 on December 2, but Apple is still signing iOS 11.1.2 at this time. Apple will likely stop signing the older update in the near future, and its end could come sooner now that further information on the tfp0 exploit has been released.
Jailbreaking iOS devices has dwindled in popularity in recent years, which has led two major Cydia repositories to close. Both ModMy and ZodTTD/MacCiti, which provided apps, themes, tweaks, and more for jailbroken iOS devices, shut down in November. For the time being, iOS 11 continues to be the only major version of iOS that has not been jailbroken.