SpectreRSB takes advantage of the process of speculative execution - a feature found in all modern CPUs that has the role of improving performance by computing operations in advance and later discarding unneeded data.

However, SpectreRSB recovers data from the speculative execution process by attacking a different CPU component involved in this 'speculation' routine, namely the Return Stack Buffer (RSB).

The academics say they've used SpectreRSB attacks to recover data belonging to other processes, and have even tricked the RSB into spilling SGX secrets.

The attack works on Intel, AMD, and ARM processors, known to use RSB. The attack can also bypass all the mitigations put in place for the original Spectre/Meltdown flaws.

So it looks like all our computers are going to get slower as the patches grind everything to a halt over a flaw in design for something that few people want in an attack that is unlikely to ever arrive.