Bug 2394574 (CVE-2025-58142)

Summary: CVE-2025-58142 xen: viridian: NULL pointer dereference by assuming the SIM page is mapped when a synthetic timer message has to be delivered
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: high    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A NULL pointer dereference vulnerability exists in Xen’s viridian implementation by assuming the synthetic interrupt message (SIM) page is mapped when delivering a synthetic timer message. A malicious x86 HVM guest with the stimer viridian extension enabled could trigger this flaw, leading to a host denial of service (crash).
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Bug Depends On: 2395157, 2395158    
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Description OSIDB Bzimport 2025-09-11 15:01:27 UTC
[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.