The Intel claim it wasn't a problem: [1]
Today, it would be a bigger deal. In the age of AI, exploiting hard to exploit holes is so much easier. AI has patience limited only by your budget.
[1] https://www.itnews.com.au/news/intel-soothes-hyperthreading-...
Linus said some silly things too. Fortunately the security and cryptography community mostly understood.