Nitrokey 3 Firmware is the the firmware of Nitrokey 3 USB keys. For release 1.8.0, and test releases with PIV enabled prior to 1.8.0, the PIV application could accept invalid keys for authentication of the admin key. This could lead to compromise of the integrity of the data stored in the application. An attacker without access to the proper administration key would be able to generate new keys and overwrite certificates. Such an attacker would not be able to read-out or extract existing private data, nor would they be able to gain access to cryptographic operations that would normally require PIN-based authentication. The issue is fixed in piv-authenticator 0.3.9, and in Nitrokey's firmware 1.8.1.

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.