IT Home, October 17 news: Technology media Decrypt published a blog post today (October 17), reporting that on yesterday (October 16) at the Hexacon offensive security conference in Paris, security firm Calif.io publicly demonstrated a "perfect jailbreak" on an iPhone 18 Pro running iOS 27.0.1, maintaining maximum privileges even after reboot.
IT Home note: Jailbreaking refers to bypassing Apple’s restrictions on iOS, such as signature verification, app sandboxing, and the protected boot chain, to grant users root access. This enables the installation of non-App Store apps, full access to the file system, deep customization of the system interface, and even the removal of preinstalled software.
Unlike traditional jailbreaks that require reconnecting the device or retriggering the vulnerability, an untethered jailbreak maintains the jailbroken state even after the device is restarted.
During the live demonstration, researchers rebooted the phone, unlocked it with a standard passcode, and immediately opened an SSH session as the root user; the terminal output confirmed the system version as iOS 27.0.1.
The media noted that the security design of modern iPhones is extremely complex; attackers typically need to chain multiple vulnerabilities to first escape the app sandbox, then gain kernel control, and bypass hardware-level protections such as pointer authentication codes. To maintain privileges after a reboot, they must also overcome Apple’s verification of boot code, which is why this demonstration attracted significant attention.
However, the public cannot currently replicate this jailbreak on their own. Calif.io has not disclosed the name of the vulnerability exploited, technical details, or any downloadable tools, stating only that the information “will be released at the appropriate time.” The company also demonstrated other projects during the conference, including a one-click Signal attack and iMessage-related demonstrations.