ApostropheCMS is an open-source Node.js content management system. Prior to 4.34.0, 'POST /api/v1/@apostrophecms/doc/slugTaken' with body { "slug": "target-slug" } returns a boolean indicating whether a slug is in use across all document types and visibility levels, with no permission or type filter. Any logged-in user (including editors) can enumerate the slug space of private pages, drafts, and archived content. This issue is fixed in version 4.34.0.