4G VoLTE is a high-speed wireless communication for mobile phones and data terminals. It is a mash-up between LTE, GSM, and VoIP, a technology used for Voice-over-the-Internet communications. Researchers from French company P1 Security have detailed a long list of issues with the new technology. They say they identified both “active”” vulnerabilities (that require modifying special SIP packets) and “”passive”” (that expose data via passive network monitoring)”
Source: https://www.bleepingcomputer.com/news/security/hackers-can-spoof-phone-numbers-track-users-via-4g-volte-mobile-technology/