Chipmaker Arm has issued guidance to software developers this week detailing mitigations against a new vulnerability discovered in its Armv8-A (Cortex-A) CPU architecture.
Codenamed SLS (standing for Straight-Line Speculation), this bug is a classic side-channel speculative execution attack.
Speculative execution refers to the concept of CPUs processing data in advance for speed and performance reasons and then discarding the computational branches they don’t need. Side-channel attacks in speculative execution allow malicious threat actors to leak (steal) these temporary computations and see what the CPU might be working on.
NOTE: For now, it looks like Raspberry Pi is still immune to these attacks
Link: Arm CPUs impacted by rare side-channel attack