CVE-2025-27466: Xen

Critical severity, CVSS 9.8. EPSS: 0.5% chance of exploitation in the next 30 days.

[This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] There are multiple issues related to the handling and accessing of guest memory pages in the viridian code: 1. A NULL pointer dereference in the updating of the reference TSC area. This is CVE-2025-27466. 2. A NULL pointer dereference by assuming the SIM page is mapped when a synthetic timer message has to be delivered. This is CVE-2025-58142. 3. A race in the mapping of the reference TSC page, where a guest can get Xen to free a page while still present in the guest physical to machine (p2m) page tables. This is CVE-2025-58143.

Affected products

• Xen Xen: from 4.13.0, before 4.17.0 (fixed in 4.17.0)

Published 2025-09-11. Last modified 2026-06-17.