Directory traversal vulnerability in the SwiftKey language-pack update implementation on Samsung Galaxy S4, S4 Mini, S5, and S6 devices allows remote web servers to write to arbitrary files, and consequently execute arbitrary code in a privileged context, by leveraging control of the skslm.swiftkey.net domain name and providing a .. (dot dot) in an entry in a ZIP archive, as demonstrated by a traversal to the /data/dalvik-cache directory.

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.