Someone correct me if I understood this wrong. The way they are exploiting speculative execution is to load values from memory regions which they don't have per

Someone correct me if I understood this wrong. The way they are exploiting speculative execution is to load values from memory regions which they don't have permission to a cache line, and when the speculation is found to be false, the processor does not undo the write to the cache line? The question is, how is the speculative write going to the cache in the first place? Only retired instructions should be able to modify cache lines AFAIK. What am I missing? Edit: Figured it out. The speculatively accessed memory value is used to compute the address of a load from a memory location which the attacker has access to. Once the mis-speculation is detected, the attacker will time accesses to the memory which was speculatively loaded and figure out what the secret key is. Brilliant!