ES File Explorer is an Android file manager with over 100,000,000 installs on the Google Play store page and over 500 million users worldwide. A hidden web server always running in the background was found by security researcher Robert Baptiste in the app. A Man-In-The-Middle (MitM) attack would allow attackers to take advantage of a Man-in-the-middle attack on the same Wi-Fi network. A fix is already waiting for approval from Google’s review team with an estimated publishing time of approximately two days.
Source: https://www.bleepingcomputer.com/news/security/es-file-explorer-flaws-put-100-million-users-data-at-risk-fix-promised/