CVE-2025-40184

Host panic via block-mapping size assertion

Published Nov 12, 2025 · Updated May 11, 2026

Denial of service in Linux KVM 6.16 through 6.17.3 allows local users to panic an arm64 host by launching a protected guest. The assert_host_shared_guest checks in __pkvm_host_relax_perms_guest and __pkvm_host_mkyoung_guest wrongly require a single-page size when the mapping can be a huge-page block. The path requires transparent huge pages and CONFIG_NVHE_EL2_DEBUG; the failed WARN_ON stops the host rather than only the guest.

CVSS severityUnavailable
Unscored
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Linux KVM 6.16 through 6.17.3 allows local users to panic an arm64 host by launching a protected guest. The assert_host_shared_guest checks in __pkvm_host_relax_perms_guest and __pkvm_host_mkyoung_guest wrongly require a single-page size when the mapping can be a huge-page block. The path requires transparent huge pages and CONFIG_NVHE_EL2_DEBUG; the failed WARN_ON stops the host rather than only the guest.

The record

CVE
CVE-2025-40184
Published
Nov 12, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 12, 2025CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=6.16
  2. Affected versionversion=f28f1d02f4eaac05c2ad6bf7264a8696dc21d011 <2ba972bf71cb71d2127ec6c3db1ceb6dd0c73173
  3. Affected versionversion=f28f1d02f4eaac05c2ad6bf7264a8696dc21d011 <4f7af3d8a1177c807d1f2563c7c171700b020656

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.16; version=f28f1d02f4eaac05c2ad6bf7264a8696dc21d011 <2ba972bf71cb71d2127ec6c3db1ceb6dd0c73173; version=f28f1d02f4eaac05c2ad6bf7264a8696dc21d011 <4f7af3d8a1177c807d1f2563c7c171700b020656

Published CVSS scores

No CVSS assessment is available in this record.

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

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

Technologies

Your stack

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Your stack

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