Yes but the Firecracker VMs are pinned to specific cores. So no two tenants never share a CPU core. Other than Rowhammer, has there been a hardware vulnerability of this nature that has worked x-core? I don't recall.
Still, I think that if your company is handling user data it's worth seriously considering dedicated instances for any service that encounters plaintext user information.
Still, I think that if your company is handling user data it's worth seriously considering dedicated instances for any service that encounters plaintext user information.