[CircleSpokes]

Intel gave it to MSI, but I may have been incorrect before. Apparently the keys was shared across multiple OEMs (at least that is how I read this below)

>The leaked private keys affect Intel’s 11th, 12th, and 13th generation processors and were distributed to various OEMs, including Intel itself, Lenovo, and Supermicro.

[Joker_vD]

...isn't such signing usually done the other way around? Intel would hold the signing keys, MSI (or any other OEM manufacturer) then sends (over a secure channel) their firmware to Intel, Intel signs it and sends the signature back.

[CircleSpokes]

I think that would make sense yes. It isn't clear to me why they would distribute the private keys to the OEMs (laziness?).