GHSA-69hx-63pv-f8f4: Ech0 has Stored XSS via SVG Upload and Content-Type Validation Bypass in File Upload

The file upload endpoint validates Content-Type using only the client-supplied multipart header, with no server-side content inspection or file extension validation. Combined with an unauthenticated static file server that determines Content-Type from file extension, this allows an admin to upload HTML/SVG files containing JavaScript that execute in the application’s origin when visited by any user. Additionally, image/svg+xml is in the default allowed types, enabling stored XSS via SVG without any Content-Type spoofing.