TypeBot is a chatbot builder tool. In versions 3.16.1 and earlier, POST /api/blocks/file-input/v3/generate-upload-url is unauthenticated and uses unsanitized fileName input to construct public/ S3 object keys, while issuing presigned PUT URLs that do not bind Content-Type. As a result, any anonymous visitor to a published bot with a file input can upload attacker-controlled HTML, SVG, or JS to attacker-chosen subpaths, including other tenants’ publicly served result paths, enabling arbitrary content hosting and potential stored XSS on the storage origin. ../ traversal is blocked by S3/MinIO canonicalization (signature mismatch), but forward-slash path injection is exploitable. This issue has been fixed in version 3.17.0.