CVE-2025-27466Public exploit

Host crash via invalid reference-TSC page mapping

Published Sep 11, 2025 · Updated Nov 4, 2025

NULL pointer dereference in Xen 4.13 and newer allows guest OS users to crash the host through Viridian reference-TSC updates. The reference-TSC update path uses the page mapping without first confirming that the mapping is valid, causing a NULL pointer dereference inside the hypervisor. Exploitation requires an x86 HVM guest with the reference_tsc Viridian extension enabled, and the resulting fault interrupts the entire host.

CVSS severity9.8
Critical
EPSS probability0.47%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

NULL pointer dereference in Xen 4.13 and newer allows guest OS users to crash the host through Viridian reference-TSC updates. The reference-TSC update path uses the page mapping without first confirming that the mapping is valid, causing a NULL pointer dereference inside the hypervisor. Exploitation requires an x86 HVM guest with the reference_tsc Viridian extension enabled, and the resulting fault interrupts the entire host.

The record

CVE
CVE-2025-27466
Published
Sep 11, 2025
Updated
Nov 4, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-395, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 11, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.5SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-395Use of NullPointerException Catch to Detect NULL Pointer Dereference
T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo