Browser tabs from different origins are equivalent of the multi-user access here, at least in cases where the speculative execution vulnerability can be exploited from JS. Same for other workloads where untrusted parties have a sufficient degree of control on what code executes.
Generally.. depends on what you mean by generally. In the casual sense of the word, speculative execution attacks are not very common, so it can be said that most people are mostly safe from them independent of mitigations. Someone might also use "generally safe" to mean proven security against a whole class of attacks, in which case the answer would be no.
Generally.. depends on what you mean by generally. In the casual sense of the word, speculative execution attacks are not very common, so it can be said that most people are mostly safe from them independent of mitigations. Someone might also use "generally safe" to mean proven security against a whole class of attacks, in which case the answer would be no.