Just one phone call away: How we accidentally built a nation-scale tracking system

What if tracking someone’s real-time location didn’t require malware, exploits, or privileged access, but just a phone call?

In 2026, a security researcher at mnemonic uncovered a critical misconfiguration in a Telia’s cellular network that allowed anyone to determine a person’s location, without leaving any trace beyond a missed call. The issue affected politicians, journalists, and security-cleared personnel.

This talk tells the story behind that discovery.