The flash read-out protection (RDP) level is not enforced during the device initialization phase of the SoloKeys Solo 4.0.0 & Somu and the Nitrokey FIDO2 token. This allows an adversary to downgrade the RDP level and access secrets such as private ECC keys from SRAM via the debug interface.

An issue was discovered in Nitrokey FIDO U2F firmware through 1.1. Communication between the microcontroller and the secure element transmits credentials in plain. This allows an adversary to eavesdrop the communication and derive the secrets stored in the microcontroller. As a result, the attacker is able to arbitrarily manipulate the firmware of the microcontroller.