They confirmed that all YubiKey 5 models can be cloned, and they also said that the vulnerability isn't limited to the brand though they've yet to try and clone other devices.

As YubiKey firmware can’t be updated, all YubiKey 5 devices before version 5.7 (or 5.7.2 for the Bio series and 2.4.0 for YubiHSM 2) will remain vulnerable forever.

The YubiKey 5, the most widely used hardware token for two-factor authentication based on the FIDO standard, contains a cryptographic flaw that makes the finger-size device vulnerable to cloning ...

Yubico responds to EUCLEAK The flaw impacts YubiKey 5 Series devices running firmware versions older than 5.7.0, which uses Infineon's flawed cryptographic library. The models impacted by EUCLEAK are: ...