[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:
A NULL pointer dereference in the updating of the reference TSC area. This is CVE-2025-27466.
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.
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.
If two threads of execution use a resource simultaneously, there exists the possibility that resources may be used while invalid, in turn making the state of execution undefined.