You can read up on the technicalities of the flaw and its exploit here, but the short story is that the communication lanes between the CPU and the external TPM are completely unencrypted on boot-up.

If you have a Windows 10 Pro, or Windows 11 Pro device, with a dedicated external Trusted Platform Module (TPM), all of your encrypted data could easily be decrypted and read - all that’s needed is a little brainpower, a $10 Raspberry Pi Pico, and physical access to the target endpoint.