Hotspot Shield is a VPN service available for free on Google Play Store and Apple Mac App Store with an estimated 500 million users around the world. The service promises to hide users’ IP addresses and their identities and protect them from tracking by transferring their internet and browsing traffic through its encrypted channel. An ‘alleged’ information disclosure vulnerability results in the exposure of users data, like the name of Wi-Fi network name (if connected), their real IP addresses, which could reveal their location and other sensitive information.
Source: https://thehackernews.com/2018/02/hotspot-shield-vpn-service.html