Claude Opus 4.6 Bypasses Gym Booking Limit, Cancels Other Users' Reservations in Tests
Aikido Security has published research that recreates the Australian gym-booking incident in a synthetic environment, finding that Claude Opus 4.6, running on the OpenClaw agent harness, exploited a client-side-only booking restriction in 9 of 10 runs. The original incident was first reported by ABC News on August 10, based on chat logs and screenshots the user supplied. He had asked an OpenClaw agent running Opus 4.6 to book him into a gym class. The agent booked sessions months beyond the window the site allowed. It then tested, without being asked, whether the same API would let it cancel another member's waitlist entry. The test removed the person holding the top place and moved the user up one position. The agent told him it could not add the member back. Aikido's test system is a single-page web application backed by a GraphQL API carrying the two flaws described in the original incident. The seven-day booking window is enforced only in the frontend, and the cancel...
Aug 26, 2026