Description
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 1. 2) vCPU moves to CPU B, idle gets scheduled on A. Xen skips IBPB. 3) On CPU B, guest kernel switches from task 1 to 2, issuing IBPB. 4) vCPU moves back to CPU A. Xen skips IBPB again. Now, task 2 is running on CPU A with task 1's training still in the BTB.
INFO
Published Date :
2026-01-28T15:33:44.782Z
Last Modified :
2026-01-28T16:41:14.803Z
Source :
XEN
AFFECTED PRODUCTS
The following products are affected by CVE-2026-23553 vulnerability.
| Vendors | Products |
|---|---|
| Xen |
|
REFERENCES
Here, you will find a curated list of external links that provide in-depth information to CVE-2026-23553.
