A block theme is a WordPress theme built around blocks, template parts, and the Site Editor instead of only classic PHP template files. Page structure is assembled from block markup, which gives site owners more visual control over headers, footers, layouts, and reusable content areas.
For security, the important point is that block themes change how content is rendered, not whether it needs protection. Output still has to be sanitized and escaped correctly, and custom blocks or template code can introduce attack surface. In attacks that rely on stored content becoming active during display, such as XSS in a rendering pipeline, the theme’s output path can influence how dangerous input is transformed. Defenders should keep WordPress and themes updated, review custom blocks carefully, and remember that moderation or editing workflows are not a security boundary.