CVE-2025-27466

[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.