How severe is CVE-2025-27466?

CVE-2025-27466 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2025-27466 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-27466?

CVE-2025-27466 affects Xen. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-27466?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2025-27466 have an EU (EUVD) identifier?

Yes. CVE-2025-27466 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-28913.

When was CVE-2025-27466 published?

CVE-2025-27466 was published on 2025-09-11 and last updated on 2026-06-17.

CVE-2025-27466

CVE-2025-27466 is a critical-severity vulnerability in Xen with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-395.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 0% (35th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-28913
Weakness: CWE-395
Affected product: Xen
Published: 2025-09-11
Last modified: 2026-06-17

Description

[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.

Frequently asked questions

What is 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.
How severe is CVE-2025-27466?: CVE-2025-27466 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2025-27466 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-27466?: CVE-2025-27466 affects Xen. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-27466?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2025-27466 have an EU (EUVD) identifier?: Yes. CVE-2025-27466 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-28913.
When was CVE-2025-27466 published?: CVE-2025-27466 was published on 2025-09-11 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:xen:xen:*:*:*:*:*:*:x86:*

More vulnerabilities in Xen

CVE-2017-10921 — Critical (CVSS 10.0): The grant-table feature in Xen through 4.8.x does not ensure sufficient type counts for a GNTMAP_device_map and…
CVE-2017-10920 — Critical (CVSS 10.0): The grant-table feature in Xen through 4.8.x mishandles a GNTMAP_device_map and GNTMAP_host_map mapping, when followed…
CVE-2017-10918 — Critical (CVSS 10.0): Xen through 4.8.x does not validate memory allocations during certain P2M operations, which allows guest OS users to…
CVE-2017-10912 — Critical (CVSS 10.0): Xen through 4.8.x mishandles page transfer, which allows guest OS users to obtain privileged host OS access, aka…
CVE-2015-8104 — Critical (CVSS 10.0): The KVM subsystem in the Linux kernel through 4.2.6, and Xen 4.3.x through 4.6.x, allows guest OS users to cause a…
CVE-2018-12892 — Critical (CVSS 9.9): An issue was discovered in Xen 4.7 through 4.10.x. libxl fails to pass the readonly flag to qemu when setting up a SCSI…

All CVEs affecting Xen →

Other CWE-395 vulnerabilities

CVE-2025-58142 — Critical (CVSS 9.8): [This CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to…
CVE-2025-15514 — High (CVSS 7.5): Ollama 0.11.5-rc0 through current version 0.13.5 contain a null pointer dereference vulnerability in the multi-modal…
CVE-2022-2832 — High (CVSS 7.5): A flaw was found in Blender 3.3.0. A null pointer dereference exists in source/blender/gpu/opengl/gl_backend.cc that…
CVE-2024-27661 — Medium (CVSS 6.5): D-Link DIR-823G A1V1.0.2B05 was discovered to contain Null-pointer dereferences in sub_4484A8(). This vulnerability…
CVE-2024-27659 — Medium (CVSS 6.5): D-Link DIR-823G A1V1.0.2B05 was discovered to contain Null-pointer dereferences in sub_42AF30(). This vulnerability…
CVE-2024-27658 — Medium (CVSS 6.5): D-Link DIR-823G A1V1.0.2B05 was discovered to contain Null-pointer dereferences in sub_4484A8(). This vulnerability…

Browse all CWE-395 vulnerabilities →