This book constitutes the refereed proceedings of the Second International Conference on Constructive Approaches for Security Analysis and Design of Embedded Systems, CASCADE 2026, held in Regensburg, Germany, during March 30–April 1, 2026. The 21 full papers included in this book were carefully reviewed and selected from 43 submissions. They are organized into topical sections as follows: Processor architecture and micro-architecture; Masking; Physical Unclonable Functions; Side-channel Analysis; and Fault Injection.