The cause of this rather straightforward vulnerability is ES File Explorer's built-in and hidden web server which runs in the background and exposes port 59777.

If you use the popular Android app ES File Explorer, make sure you are on the latest version so you are safe from the previous security vulnerability.

Popular application ES File Explorer for Android has a significant vulnerability, putting your data at risk. Learn what's involved and how to remediate the threat.

File Explorer apps are fairly common on Android, but if you have this one installed on your phone, you probably want to remove it sooner rather than later.

ES File Explorer and FileZilla are free software that can be used to transfer data between Android Phones/Tablets & Windows PC wirelessly.