Most mobile calls around the world are made over the Global System for Mobile Communications standard; in the US, GSM underpins any call made over AT or T-Mobile's network.

And the vulnerability has been around for decades.

Regular GSM calls aren't fully end-to-end encrypted for maximum protection, but they are encrypted at many steps along their path, so random people can't just tune into phone calls over the air like radio stations.

"GSM is a well documented and analyzed standard, but it’s an aging standard and it's had a pretty typical cybersecurity journey," says Campbell Murray, the global head of delivery for BlackBerry Cybersecurity.

"The weaknesses we found are in any GSM implementation up to 5G.

Regardless of which GSM implementation you’re using there is a flaw historically created and engineered that you’re exposing."

The Samsung Galaxy Note 10 is finally available, alongside Samsung’s latest 5G phone, the Galaxy Note 10+ 5G.

At launch, the Galaxy Note 10+ 5G will only be available on Verizon, but eventually, it’ll make its way to other carriers too.

And, when that happens, the T-Mobile variant will be the first phone to leverage T-Mobile’s powerful 600MHz spectrum, according to a new tweet from T-Mobile chief technology officer Neville Ray.

5G is often associated with millimeter-wave frequencies, which are the ultra-high frequencies that can transmit a lot of data at shorter distances.

But carriers are also building out other frequencies with 5G too, such as the low-band frequencies that can travel further distances, and the mid-band frequencies that offer a compromise between the two.

T-Mobile’s 600MHz frequency band is one of those low-band frequencies that’s able to travel much longer distances than mmWave frequencies.