Shadow paging errors in the Xen hypervisor can switch page tables without updating the running virtual CPU reference. The resulting mismatch between loaded page tables and mapcache metadata can corrupt the mapcache, potentially leading to loss of data integrity or hypervisor instability. This flaw aligns with CWE‑119 (Buffer Correctness).

The vulnerability affects the Xen hypervisor, specifically any Xen build that implements the described shadow paging paths. No specific version range is provided, so all current Xen deployments that contain these code paths are potentially impacted.

The CVSS score of 8.1 indicates high severity. Exploitation would likely require an attacker to control a guest VM that can trigger the shadow paging bug; the EPSS score is currently unavailable, so the likelihood of real‑world exploitation is unknown. The vulnerability is not listed in CISA’s KEV catalog. Users can mitigate by limiting guest types to HVM or PVH, or by running PV guests in the PV shim as provided by Xen. Failure to mitigate may leave the hypervisor prone to corruption when the bug is triggered.