Measuring AI Agents' Progress on Multi-Step Cyber Attack Scenarios. - Linus Folkerts; Will Payne; Simon Inman; Philippos Giavridis; Joe Skinner; Sam Deverett; James Aung; Ekin Zorer; Michael Schmatz; Mahmoud Ghanem; John Wilkinson; Alan Steer; et al. (CoRR, 2026)