For weeks, the experts in security had been saying that FBI does not in fact need Apple's help to get into that phone; that they are just posturing in order to obtain a back door.
This was posted on the ACLU website:
https://www.aclu.org/blog/free-future/one-fbis-major-claims-...
The FBI can simply remove this chip from the circuit board (“desolder” it), connect it to a device capable of reading and writing NAND flash, and copy all of its data. It can then replace the chip, and start testing passcodes. If it turns out that the auto-erase feature is on, and the Effaceable Storage gets erased, they can remove the chip, copy the original information back in, and replace it. If they plan to do this many times, they can attach a “test socket” to the circuit board that makes it easy and fast to do this kind of chip swapping.
Maybe the FBI has a secret new exploit --- or maybe they just did the above method, getting the "third party" help with the desoldering and the attachment of a socket, and hardware for reading NAND.
It's just speculation.
Even if the FBI are exploiting some hole, that is better than them having a back door, which is essentially a security hole put in by design.
The article is speculating, and it's conflating security holes with back doors.