A few days ago it was announced that it is possible to bypass Ledger's Security Keycard verification:
https://medium.com/@niv_28183/ledger-hw-1-nano-security-keycard-bypass-dc868f2893

Affected are Ledger HW.1 and Ledger Nano, attack requires physical access to the device.
Company has confirmed the problem:https://donjon.ledger.com/lsb/017/