The Import XML and RSS Feeds WordPress plugin before 2.1.5 contains a web shell, allowing unauthenticated attackers to perform RCE. The plugin/vendor was not compromised and the files are the result of running a PoC for a previously reported issue (https://wpscan.com/vulnerability/d4220025-2272-4d5f-9703-4b2ac4a51c42) and not deleting the created files when releasing the new version.