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

CVE-2026-23553 is an issue in the Xen hypervisor: during context switches, Xen may skip IBPB when a vCPU returns to the same physical CPU, potentially allowing stale BTB/GPU state to persist across tasks and undermine guest kernel isolation. The advisory chain shows the vulnerability is tied to i...

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 ...