Reading of local files through manipulation of form autocomplete — Mozilla

Security researcher Armin Ebert reported that a user readable file in a known local path could be uploaded to a malicious site. This was done by manipulating the autocomplete feature in a form and user interaction with it. While the local file is not visibly uploaded through the form, its contents are made available through the Document Object Model (DOM) to script content on the attacking page, leading to information disclosure.