Key facts
- Calif.io demonstrated an untethered jailbreak on an iPhone 18 Pro running iOS 27.0.1.
- The jailbreak survived a reboot, returning root access without a computer.
- AI models from Claude and Anthropic Research assisted in identifying vulnerabilities for the exploit.
- Apple's iOS 27 security notes credit Calif.io for two unrelated crash bugs.
Security firm Calif.io demonstrated an untethered jailbreak on an iPhone 18 Pro running iOS 27.0.1 at Hexacon in Paris on Friday. This marks the first successful untethered, permanent jailbreak on such devices, allowing users to bypass Apple's software restrictions and gain root access that persists after a restart without external computer connection. Apple typically builds iPhones as locked-down systems, but a jailbreak allows users to install unapproved apps, customize the interface, and use the phone in ways Apple did not intend. Video of the demonstration showed the team rebooting the phone and opening an SSH session as root. Calif.io has not yet disclosed the specific vulnerabilities used or released a tool, stating that details will be published later. Apple's iOS 27 security notes credit Calif.io, in collaboration with Claude and Anthropic Research, for two unrelated bugs that caused system crashes, though these are not explicitly linked to the jailbreak.