The Cyber Due Diligence Object Model (CDDOM) is a structured, extensible framework designed for SMEs to manage cybersecurity due diligence in digital supply chains. Aligned with regulations like NIS2, DORA, CRA, and GDPR, CDDOM enables continuous, automated, and traceable due diligence. It integrates descriptive schemas, role‑specific messaging, and decision support to facilitate supplier onboarding, risk reassessment, and regulatory compliance. Validated in real‑world scenarios, CDDOM supports automation, transparency, and interoperability, translating compliance and trust signals into machine‑readable formats. It fosters resilient, decision‑oriented cyber governance, addressing modern cybersecurity challenges outlined in recent research.