The SwiftKey language-pack update implementation on Samsung Galaxy S4, S4 Mini, S5, and S6 devices relies on an HTTP connection to the skslm.swiftkey.net server, which allows man-in-the-middle attackers to write to language-pack files by modifying an HTTP response.  NOTE: CVE-2015-4640 exploitation can be combined with CVE-2015-4641 exploitation for man-in-the-middle code execution.