CVE-2026-23553

In the context switch logic Xen attempts to skip an IBPB in the case of a vCPU returning to a CPU on which it was the previous vCPU to run. While safe for Xen's isolation between vCPUs, this prevents the guest kernel correctly isolating between tasks. Consider: 1 vCPU runs on CPU A, running task ...

CVE-2026-23553

In the context switch logic Xen attempts to skip an IBPB in the case of a vCPU returning to a CPU on which it was the previous vCPU to run. While safe for Xen's isolation between vCPUs, this prevents the guest kernel correctly isolating between tasks. Consider: 1 vCPU runs on CPU A, running task ...

CVE-2026-23553

The Xen hypervisor contains a flaw in its context switch logic where it attempts to skip an Indirect Branch Prediction Barrier (IBPB) when a vCPU returns to a CPU where it was the previous vCPU to run. While this maintains isolation between vCPUs, it prevents the guest kernel from correctly isola...