Yubico issued a security advisory saying that an issue impacting YubiKey FIPS Series devices (versions 4.4.2 and 4.4.4) reduces the strength of generated RSA keys and ECDSA signatures after power-up.
YubiKey FIPS Series key affected by this issue are the YubiKey FIPS, the YubiKey Nano FIPS, the YubiKey C FIPS, and the YubiKey C Nano FIPS — other Yubico products are not impacted.
According to Yubico's advisory, "random values leveraged in some YubiKey FIPS applications contain reduced randomness for the first operations performed after YubiKey FIPS power-up."
