Gotenberg allows Chromium URL conversion routes to read arbitrary files under /tmp via file:// scheme
The /forms/chromium/convert/url and /forms/chromium/screenshot/url routes accept url=file:///tmp/… from anonymous callers. The default Chromium deny-list intentionally exempts file:///tmp/ so HTML/Markdown routes can load their own request-local assets, and those routes apply a per-request AllowedFilePrefixes guard to scope the read. The URL routes never set AllowedFilePrefixes, so the scope guard silently skips. Alice enumerates /tmp/, walks Gotenberg's per-request working directories, and reads the raw source files of other in-flight conversions as rendered …