Hardware-level CPU vulnerabilities like Meltdown are disproportionately dangerous in multi-tenant cloud environments because multiple customers share the same physical processor. A vulnerability that leaks kernel memory can be used to read data belonging to co-located tenants — "adjacent machine compromise." **Why cloud amplifies the risk**: - *Containers*: Multiple tenants share a single OS kernel; kernel memory leaks expose all co-tenants simultaneously - *Hypervisors*: On EC2/Azure Hyper-V, tenants co-reside on the same physical CPU — speculative reads can cross VM boundaries - *Attack surface*: On-premises Meltdown requires local code execution. In the cloud, renting a micro-instance next to a target suffices **2018 response pattern**: AWS, Azure, and OVH each required mandatory forced reboots of all hosted VMs within days — confirming that cloud providers carry systemic exposure to hardware vulnerabilities, regardless of their software stack. **Cross-domain relevance**: - *Cloud architecture*: Justifies the shift toward single-tenant bare-metal cloud options for sensitive workloads - *Risk management*: Hardware vulnerabilities in shared infrastructure are systematically harder to disclose — patches require coordinating OS vendors, cloud providers, and hardware manufacturers simultaneously - *Security pricing*: Dedicated hardware isolation (bare-metal instances) commands a premium precisely because multi-tenancy creates correlated risk