Source: https://msrc-blog.microsoft.com/blog/2021/02/continuing-to-listen-good-news-about-the-security-update-guide-api/
Based on user feedback we have simplified programmatic access to the security update data by removing the authentication and API-Key requirements when using the CVRF API. You will no longer have to log in to obtain a personal API key to access the data. We’re happy to make this valuable public information more freely available and accessible.
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