When the HTML backend renders pages in a headless browser using `HTMLBackendOptions(render page=True)`, the `enable local fetch` option is not enforced. The function `HTMLDocumentBackend. get browser request block reason` allows `file:` URLs unconditionally, failing to confine local requests to the source document directory. This allows a crafted HTML file to embed arbitrary local text files (such as `.env` or credential files) into a browser-rendered page image when the `playwright` dependency is installed and the input is provided as a filesystem `Path`. This disclosure is passive, as only content rendered visibly within the page viewport is captured.