Security is never finished. That conviction is where the Secure Future Initiative (SFI) started two years ago and continues to guide us today. AI is reshaping cybersecurity. Cyberattackers can discover vulnerabilities, chain attack paths, and scale exploitation faster than manual approaches allow. Defenders can use the same advances to identify risk, strengthen protections, and accelerate response. As the threat landscape evolves, security must evolve with it. This latest SFI progress report shows how Microsoft is adapting to that reality: strengthening security foundations for an AI-accelerated cyberthreat landscape, applying AI to improve security outcomes at scale, and preparing for future challenges such as scalable quantum computing. This report organizes our progress into three outcome-driven themes—secure foundations, proactive defense, and future-ready security—and shares lessons learned, practical guidance, and deeper insights across the culture, governance, principles, and engineering pillars that underpin security at Microsoft. Secure foundations The most consequential security failures rarely come from a single missing control. They come from environments where identity gaps, unmanaged assets, and inconsistent configurations sit side by side, creating composite attack paths that determined threat actors can chain together. SFI addresses this systemically, strengthening security across our environment. The results show the progress: - Phishing-resistant multifactor authentication now protects 99.97% of user/device pairs at Microsoft. - More than 732,000 resources have had public access revoked, with network isolation scaling across 1 million resources. - 1.4 million unused apps were decommissioned and cross-boundary credential isolation reached 98.7%. - Engineering defaults now prevent 83% of pipelines from accessing unapproved package endpoints. These controls form reinforcing layers: identity feeds access governance, access governance feeds segmentation, segmentation contains blast radius, and engineering defaults reduce what enters production in the first place. One of the lessons we have learned is that foundations are durable only when they’re continuously validated, not periodically audited.