Overview
- Calif, which disclosed the work Thursday in a Substack post, says it briefed Apple in person, and Apple has not commented as the firm withholds a full report until a fix.
- The exploit is a data-only local privilege escalation on macOS 26.4.1 that starts from an unprivileged user using normal system calls and ends with a root shell.
- It targets bare-metal M5 hardware with kernel Memory Integrity Enforcement enabled and links two vulnerabilities into a working path.
- Calif says Anthropic’s Mythos Preview helped find the bugs and speed development, though researchers still had to craft the bypass for Apple’s new protections.
- Access to Mythos is limited to select partners, and prior tests by Mozilla and the U.K. AI Security Institute reported the model could surface many flaws and run complex attack simulations.