Modern cybersecurity threats are growing in complexity, targeting increasingly intricate & interconnected systems. To effectively defend against these evolving threats, security teams utilize automation & orchestration to enhance response efficiency and consistency. In that sense, cybersecurity playbooks are key enablers, providing a structured, reusable, and continuously improving approach to incident response, enabling organizations to codify requirements, domain expertise, and best practices and automate decision-making processes to the extent possible. The emerging Collaborative Automated Course of Action Operations (CACAO) standard defines a common machine-processable schema for cybersecurity playbooks, facilitating interoperability for their exchange and ensuring the ability to orchestrate and automate cybersecurity operations. However, despite its potential and the fact that it is a relatively new standardization work, there is a lack of tools to support its adoption and, in particular, the management & lifecycle development of CACAO playbooks, limiting their practical deployment. Motivated by the above, this work presents the design, development, and evaluation of a Knowledge Management System (KMS) for managing CACAO cybersecurity playbooks throughout their lifecycle, providing essential tools to streamline playbook management. Using open technologies & standards, the proposed approach fosters standards-based interoperability & enhances the usability of state-of-the-art cybersecurity orchestration & automation primitives. To encourage adoption, the resulting implementation is released as open-source, which, to the extent of our knowledge, comprises the first publicly available & documented work in this domain, supporting the broader uptake of CACAO playbooks & promoting the widespread use of interoperable automation and orchestration mechanisms in cybersecurity operations.