The CakeResponse::download() method in lib/Cake/Network/CakeResponse.php constructs a Content-Disposition header by directly interpolating a caller-supplied filename into a quoted-string value without sanitization. Two distinct injection vectors exist in the unpatched code. First, if the filename contains C0 control characters (CR or LF), PHP refuses to emit the entire Content-Disposition header, silently dropping the attachment disposition. The response body is then served with its own Content-Type (for example text/html for an .html attachment) and renders inline in the browser on the application origin, creating a stored cross-site scripting condition. The commit message notes this is reachable even when the download_attachments_on_load setting is enabled, meaning a victim merely needs…