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 vulnerability in its context switch logic where it incorrectly skips an Indirect Branch Prediction Barrier (IBPB) . Specifically, when a vCPU returns to a CPU it previously occupied, the skip prevents the guest kernel from properly isolating between tasks. This can r...